Intravascular Ultrasound (IVUS) and Chromaflo Imaging Use to Decrease Contrast Load in Complex PCI With Rotational Atherectomy

Editor's note: The print version of this article contained incorrect images (corrected here). CLD regrets the error.

Videos:

Note: The 3 angiograms shown here using contrast are the only angiograms performed during the entire procedure.

Video 1. Initial angiogram of the left coronary system in RAO caudal projection.

Video 2. Angiogram of rotational atherectomy in the LAD from RAO cranial projection, which also demonstrates the relation of the diseased segment to the radiopaque guide catheter.

Video 3. Angiogram of proximal LAD in LAO caudal projection prior to deployment of the ostial LAD stent to confirm appropriate positioning.

Video 4. Final angiogram prior to finishing the procedure, showing successful results.

Abstract

We present a case of non-ST elevation myocardial infarction complicated by cardiogenic shock requiring intra-aortic balloon pump placement and acute renal failure due to contrast-induced nephropathy over pre-existing chronic kidney disease. Due to severe atherosclerotic coronary artery disease and heavy calcification in the coronaries, rotational atherectomy (1.75 mm burr followed by a 2 mm burr) was used during the percutaneous coronary intervention. The total amount of contrast administered during the procedure was limited to <20 mL with the help of an Eagle Eye Platinum ST IVUS Catheter and Chromaflo imaging (Philips Volcano). 

Case Report

A 69-year-old Caucasian female presented to an outside hospital with a non-ST elevation myocardial infarction. She underwent diagnostic coronary angiography which showed a non-obstructive left main and left circumflex, a heavily calcified proximal 90% left anterior descending (LAD) stenosis, and a chronic total occlusion (CTO) of the mid right coronary artery (RCA) receiving collaterals from LAD territory. Her past medical history was significant for type 2 diabetes, hypertension, hyperlipidemia, peripheral arterial disease, and Stage 4 chronic kidney disease (CKD) with a baseline creatinine of 2.1-2.2 and an estimated glomerular filtration rate (eGFR) of 22 mL/min/1.73 m². She was transferred to our hospital for urgent coronary artery bypass graft surgery (CABG), but had severe hemodynamic compromise during preoperative anesthesia induction, with hypotension requiring intra-aortic balloon pump (IABP) placement. She developed oliguric acute kidney injury and subsequently acute renal failure. Hence, she was considered very high risk for surgery and a decision for percutaneous coronary intervention (PCI) was made due to cardiogenic shock and evidence of ongoing active ischemia.

The patient was taken to the cardiac catheterization lab in our hospital, where her left coronary system was engaged with an 8 French (Fr) Extra Back Up (EBU) 3.5 90 cm guide (Medtronic). In the right anterior oblique (RAO) caudal projection, a scant 3-4 mL contrast was burst injected under continuous fluoroscopy, which was then saved and used as the reference angiogram. A Runthrough wire (Terumo) was carefully advanced across the LAD stenosis using the roadmap of saved fluoroscopy images, as well as visible calcification of the LAD and tactile feedback, without using additional contrast. The angiographic view was changed to the RAO cranial projection, positioning the radiopaque guide catheter at the proximal end of the LAD calcification, using this as a new reference for the rest of case. 

Figure 1. RAO cranial view showing calcified arteries, and the Eagle Eye Platinum ST IVUS Catheter (Philips Volcano) for measuring and estimating lesion length.

An Eagle Eye Platinum ST Intravascular Ultrasound (IVUS) catheter (Volcano Philips) was advanced into the proximal LAD, though was unable to advance across the lesions due to critical calcific stenosis. This landmark in relation to the guide catheter was noted, and the Runthrough wire was exchanged for a Rotofloppy wire (Boston Scientific) by using a Finecross catheter (Terumo). A 1.75 mm rotational atherectomy burr (Boston Scientific) was used to ablate the calcified plaque, followed by repeat IVUS imaging to rule out dissection and estimate vessel size. A 2 mm rotational atherectomy burr was subsequently used for further ablation of the calcified plaque. Additional IVUS imaging was performed to rule out coronary dissection, and to confirm distal coronary patency and flow using ChromaFlo (Volcano Philips). Lesion length and vessel diameter were established with the assistance of radio-opaque markings on the IVUS catheter, and the stent landing zones were simultaneously estimated by their relation to the guide catheter. 

A Xience Alpine 2.5 x 38 mm drug-eluting stent (DES) (Abbott Vascular) was carefully advanced into the mid LAD and deployed, followed by IVUS assessment for adequate stent apposition and to determine the remaining lesion length in the proximal LAD. Subsequently, a Xience Alpine 3.25 x 33 mm DES was advanced to the ostial and proximal LAD, with 2-3 mm satisfactory overlap with the distal stent visualized. At this point, the view was changed to left anterior oblique (LAO) caudal angulation for better visualization of the left main bifurcation. Another 4-5 mL of contrast was burst injected to confirm the optimal ostial location of the proximal stent edge, without extension into the distal left main or ostial left circumflex. The stent was deployed and overlap at the distal stent edge was post dilated with a noncompliant balloon to smooth the transition. A final IVUS was done to assess stent apposition with ChromaFlo for patency of the side branches and distal vessel. A final rotating angiogram was done with 10 mL of contrast that revealed excellent results with no residual stenosis, intact flow in all side branches, and no dissections or distal coronary perforation.

Figure 2. ChromaFlo in the infarct-related artery post procedure, demonstrating good flow with no dissection plane.

The patient had the IABP discontinued the following day. After a prolonged hospital course and complete recovery of her renal function with no further need for hemodialysis, she was discharged home, and has subsequently been seen for follow-up in the outpatient clinic with return to her prior functional status. 

Discussion

There is a wide variation in the reported incidence of contrast-induced nephropathy (CIN) after PCI, estimated at 7.1%, with 0.3% of patients requiring dialysis, from a study based on the American College of Cardiology’s National Cardiovascular Data Registry (ACC-NCDR) CathPCI registry.¹ The occurrence of CIN is also associated with a significantly increased risk of major adverse cardiovascular events, including cardiovascular death.^1,2 The volume of the contrast used during the procedure is strongly linked to in-hospital incidence of nephropathy requiring dialysis and poor outcomes.^3,4 Furthermore, pharmacokinetic studies exist to support the volume of contrast to baseline eGFR ratio as predictive of post procedural increases in serum creatinine.⁵ As a general rule, it is accepted that the volume of contrast received should be less than twice the patient’s baseline eGFR. 

Preprocedural strategies to decrease the incidence of contrast-induced nephropathy are well described and include adequate intravenous hydration, avoidance of nephrotoxic drugs, and the use of N-acetylcysteine and statins. 

Using as low as reasonably achievable (ALARA) contrast media has recently gained more attention, due to the above-mentioned facts. However, intraprocedural strategies to accomplish this are not as well defined in the literature. The few strategies described include use of low-osmolar and iso-osmolar contrast materials, power injectors instead of traditional hand injection, and using lower French-size diagnostic catheters. One study reported a higher mean contrast volume via radial access compared to femoral access in post-CABG patients⁶, which suggests a femoral approach may be safer in this population. The MOZART trial showed that the routine use of IVUS during PCI helps to significantly decrease the volume of contrast used.⁷ 

Our patient had several risk factors that are well known to cause and predict post procedural acute renal failure and adverse outcomes, including type 2 diabetes, hypertension, hyperlipidemia, peripheral arterial disease, and stage 4 CKD. In addition, there were multiple high risk procedural characteristics, including an urgent procedure, use of an IABP, and complex PCI with rotational atherectomy. In this patient, there was a clear necessity for significantly limiting the volume of contrast. The intraprocedural techniques we use in our lab and describe in this case allow optimal ALARA in such clinical contexts. 

The use of the GuideLiner (Vascular Solutions) during contrast injection has been shown to decrease the amount of contrast used, though we often limit this technique for the sake of cost effectiveness in patients at low risk of CIN. Calcifications in the coronary arteries are viable landmarks, particularly when combined with fixed angles and magnifications, and the use of reference images. During an typical injection, a significant amount of contrast is wasted with reflux into the aortic root, though this is not routinely necessary when either IVUS is used or the index of suspicion for an ostial lesion is low (supported by the absence of pressure dampening and ventricularization upon guide/diagnostic catheter engagement). In order to completely visualize the coronary artery, contrast injection can be stopped when the dye reaches the distal artery, avoiding long injections. With advanced operator experience, a timed injection technique where only a small volume of contrast is burst injected synchronously with the diastolic filling of the coronaries can further limit the contrast used. 

As previously described by other operators and studies, we routinely use IVUS for complex PCI cases to decrease the amount of contrast used. In addition, we specifically utilize the Eagle Eye Platinum ST IVUS, which has unique radiopaque markings at the tip that measure 36 mm end-to-end for estimation of optimal lesion and stent length. We use ChromaFlo imaging at the end of each complex intervention to assess for adequate stent apposition, and to rule out side branch occlusion and edge dissections to obviate the need for traditional “puff” imaging and additional standard angiograms. We also limit the total number of angiographic loops by doing single rotational imaging of the coronaries at the end of the case. 

Acknowledgments. Dr. Kapoor, the primary operator, would like to acknowledge Dr. William Lombardi from the University of Washington for his inspiration in using ChromaFlo to reduce contrast use.

References

1. Tsai TT, Patel UD, Chang TI, et al. Contemporary incidence, predictors, and outcomes of acute kidney injury in patients undergoing percutaneous coronary interventions: insights from the NCDR Cath-PCI Registry. J Am Coll Cardiol Intv. 2014; 7: 1-9.
2. James MT, Ghali WA, Knudtson ML, Ravani P, Tonelli M, Faris P, et al. Alberta Provincial Project for Outcome Assessment in Coronary Heart Disease (APPROACH) Investigators. Associations between acute kidney injury and cardiovascular and renal outcomes after coronary angiography. Circulation. 2011; 123: 409-416. doi: 10.1161/CIRCULATIONAHA.110.970160.
3. Freeman RV, O’Donnell M, Share D, et al. Nephropathy requiring dialysis after percutaneous coronary intervention and the critical role of an adjusted contrast dose. Am J Cardiol. 2002; 90: 1068-1073.
4. Kane GC, Doyle BJ, Lerman A, Barsness GW, Best PJ, Rihal CS. Ultra-low contrast volumes reduce rates of contrast-induced nephropathy in patients with chronic kidney disease undergoing coronary angiography. J Am Coll Cardiol. 2008; 51: 89-90
5. Laskey WK, Jenkins C, Selzer F, et al; NHLBI Dynamic Registry Investigators. Volume-to-creatinine clearance ratio: a pharmacokinetically based risk factor for prediction of early creatinine increase after percutaneous coronary intervention. J Am Coll Cardiol. 2007; 50: 584-590.
6. Michael TT, Alomar M, Papayannis A, Mogabgab O, Patel VG, Rangan BV, Luna M, et al. A randomized comparison of the transradial and transfemoral approaches for coronary artery bypass graft angiography and intervention: the RADIAL-CABG Trial (RADIAL Versus Femoral Access for Coronary Artery Bypass Graft Angiography and Intervention). JACC Cardiovasc Interv. 2013 Nov; 6(11): 1138-1144. doi: 10.1016/j.jcin.2013.08.004. 
7. Mariani J Jr, Guedes C, Soares P, Zalc S, Campos CM, Lopes AC, Spadaro AG, et al. Intravascular ultrasound guidance to minimize the use of iodine contrast in percutaneous coronary intervention: the MOZART (minimizing contrast utilization with IVUS guidance in coronary angioplasty) randomized controlled trial. JACC Cardiovasc Interv. 2014; 7: 1287-1293.

¹Cardiovascular Diseases Fellow, Augusta University - Medical College of Georgia, Augusta, Georgia; ²Assistant Professor of Medicine, Medical Director, Cardiac Care Unit, Associate Program Director, Internal Medicine Residency; ³Associate Professor of Medicine, Director, Catheterization Laboratory 
Augusta University - Medical College of Georgia, Department of Internal Medicine, Section of Cardiology, Augusta, Georgia

Disclosure: The authors report no conflicts of interest regarding the content herein.

The authors can be contacted via Arun K. Nagabandi, MBBS, at arunnagabandi@gmail.com.