Utility of Intravascular Ultrasound Guidance in Patients Undergoing Percutaneous Coronary Intervention for Type C Lesions

Investigations of injection strategies to use heparinized normal saline instead of contrast media for intracoronary optical coherence tomography imaging

BACKGROUND

The benefits of intravascular imaging-guided percutaneous coronary interventions (PCI) are well established. Intravascular imaging guidance improves short- and long-term outcomes, especially in complex PCI. Optical coherence tomography (OCT) has a higher resolution than intravascular ultrasound. However, the usage of OCT is mainly limited by the need to use contrast for flushing injections, which increases the risk of contrast-induced acute kidney injury, especially in patients with underlying chronic kidney disease. The aim of this study was to prove that flushing techniques with normal saline instead of contrast can be used in OCT imaging and can generate high-quality images.

METHODS

This prospective single-center observational study included patients with indications for OCT-guided PCI. For OCT pullbacks, heparinized saline was injected by an automatic pump injector at different rates, and additional extension catheters for selective coronary artery engagement were used at the operator's discretion. Recordings were made using the Ilumien Optis OCT system (Abbott) and the Dragonfly (Abbott) catheter and were analyzed at 1-mm intervals by two operators. Pullbacks were categorized as having optimal, acceptable, or unacceptable imaging quality. A clinically usable run was determined if >75% of the region of interest length was described as having optimal or acceptable imaging quality.

RESULTS

A total of 32 patients were enrolled in the study; 47 different lesions were assessed before and after PCI. In total, 91.5% of runs were described as clinically suitable for use.

CONCLUSION

Heparinized saline injections for OCT imaging are effective in generating good-quality OCT images suitable for clinical use.

Safety and feasibility of intravascular ultrasound-guided robotic percutaneous coronary intervention

OBJECTIVE

Previous studies have demonstrated the benefit of intravascular ultrasound (IVUS)-guided percutaneous coronary intervention (PCI) for preventing longitudinal geographic miss (LGM). However, it is yet unclear whether IVUS guidance is useful for robotic-PCI (robotic-assisted perctaneous coronary intervention [R-PCI]).

METHODS

A total of 58 consecutive patients with stable angina who underwent IVUS-guided R-PCI were enrolled. The stent landing position was angiographically marked using a balloon marker before stenting, followed by measurements of the expected stent length using balloon pullback. Subsequently, prestenting IVUS was performed to determine stent landing. All pre-PCI IVUS images were assessed for lesion length and percent plaque volume (%PV) using both IVUS and angiographic marking. LGM was defined as a residual %PV >50% at either the distal or proximal stent edge, any stent edge dissection, or additional stent deployment immediately after stenting.

RESULTS

The included patients had an average age of 67.1 ± 10.1 years. IVUS guidance had significantly longer lesion lengths compared with angiographic marking. Based on IVUS-guided stent deployment, nine cases exhibited LGM immediately after stenting. IVUS-marked landing points had a significantly smaller %PV and significantly larger lumen area compared with those for angiography.

CONCLUSION

IVUS-guided R-PCI was well-tolerated and may be better at preventing LGM compared with angiography-guided R-PCI.

Comparison of Long-Term Outcomes Between Intravascular Ultrasound-, Optical Coherence Tomography- and Angiography-Guided Stent Implantation: A Meta-Analysis

Intravascular ultrasonography (IVUS) and optical coherence tomography (OCT) guided percutaneous coronary interventions (PCI) are alternative techniques to angiography-guided (ANG-g) PCI in patients with coronary artery disease (CAD), especially for optimal stent deployment in coronary arteries. We conducted a network meta-analysis including studies comparing those three techniques. We searched databases for studies that compared IVUS, OCT, and ANG-g PCI in patients with CAD. Overall, 52 studies with 231,137 patients were included in this meta-analysis. ANG-g PCI had higher major adverse cardiovascular events (MACEs), all-cause death, cardiac death, myocardial infarction (MI), target lesion revascularization (TLR), and stent thrombosis (ST) than IVUS-guided PCI. Of note, both OCT-guided and IVUS-guided PCI had similar outcomes. The frequency of MACEs, cardiac death, and MI were higher in ANG-g PCI than in OCT-guided PCI. The highest benefit was established with OCT for MACEs (P-score=.973), MI (P-score=.823), and cardiac death (P-score=.921) and with IVUS for all-cause death (P-score=.792), TLR (P -score=.865), and ST (P-score=.930). This network meta-analysis indicated that using OCT or IVUS for optimal stent implantation provides better outcomes in comparison with ANG-g in patients with CAD undergoing PCI.

Comparison of angiographic and intravascular ultrasound vessel measurements in infra-popliteal endovascular interventions: The below-the-knee calibration study

BACKGROUND

Endovascular revascularization (ER) via percutaneous transluminal angioplasty (PTA) and stenting are viable options for revascularization in below-the-knee (BTK) peripheral arterial disease. Two-dimensional angiography has been the standard of practice for estimating vessel size and selecting treatment devices during ER. However, in other vascular territories, intravascular ultrasound (IVUS) offers better visualization of the lumen dimensions.

PURPOSE

To compare angiographic and intravascular ultrasound reference vessel (lumen) measurements in below-the-knee peripheral artery interventions.

METHODS

20 consecutive patients were enrolled in the BTK Calibration study from 2 sites in the United States and Australia. Patients with at least one diseased segment in a native infra-popliteal artery (below-the-knee) and a clinical indication for endovascular therapy (EVT) were included with no limitations with regards to vessel diameter or lesion length. Digital subtraction angiography and intravascular ultrasound imaging were collected pre-and post-percutaneous transluminal angioplasty and images were sent to an independent Core lab for standardized quantitative analysis of the normal-looking reference vessel dimensions when available. The results were presented as least square means with 95% confidence intervals and a p-value of <0.05 was considered as significant.

RESULTS

The overall (N = 19) mean reference vessel diameter for QVA was 2.98 ± 1.24 vs. 3.47 ± 0.72 for IVUS (mean difference was -0.50, (95% CI: -0.80, -0.20; p = 0.14). As expected in the proximal segments (N = 12), the mean reference vessel diameters were larger: for QVA was 3.17 ± 1.34 vs. 3.55 ± 0.76 in IVUS, (mean difference was -0.38, (95% CI:-0.79,0.03; p = 0.40); while in the distal segments (N = 7), mean reference vessel diameters were smaller: for QVA was 2.64 ± 1.06 vs. 3.33 ± 0.67 in IVUS, (mean difference was -0.69, (95% CI:-1.04,-0.34; p = 0.17). We observed a greater degree of acute gain in cases where the treatment balloon size correlated with the IVUS measured reference size.

CONCLUSION

Angiography underestimates infrapopliteal reference vessel lumen size even when quantitatively assessed. Adjunctive IVUS imaging use in guiding BTK procedures could help ensure adequate sizing and possibly impact immediate post-procedure indices.

Intravascular Ultrasound Imaging-Guided Versus Coronary Angiography-Guided Percutaneous Coronary Intervention: A Systematic Review and Meta-Analysis

Background

Intravascular ultrasound (IVUS) guidance during percutaneous coronary intervention (PCI) offers tomographic images of the coronary vessels, allowing optimization of stent implantation at the time of PCI. However, the long‐term beneficial effect of IVUS over PCI guided by coronary angiography (CA) alone remains under question. We sought to investigate the outcomes of IVUS‐guided compared with CA‐guided PCI.

Methods and Results

We performed a comprehensive search of PubMed, Medline, and Cochrane Central Register, looking for randomized controlled trials and observational studies that compared PCI outcomes of IVUS with CA. Data were aggregated for the primary outcome measure using the random‐effects model as pooled risk ratio (RR). The primary outcomes were the rate of cardiovascular death, need for target lesion revascularization, occurrence of myocardial infarction, and rate of stent thrombosis. A total of 19 studies met the inclusion criteria, comprising 27 610 patients divided into IVUS (n=11 513) and CA (n=16 097). Compared with standard CA‐guided PCI, we found that the risks of cardiovascular death (RR, 0.63; 95% CI, 0.54–0.73), myocardial infarction (RR, 0.71; 95% CI, 0.58–0.86), target lesion revascularization (RR, 0.81; 95% CI, 0.70–0.94), and stent thrombosis (RR, 0.57; 95% CI, 0.41–0.79) were all significantly lower using IVUS guidance.

Conclusions

Compared with standard CA‐guided PCI, the use of IVUS imaging guidance to optimize stent implantation is associated with a reduced risk of cardiovascular death and major adverse events, such as myocardial infarction, target lesion revascularization, and stent thrombosis.

Intravascular ultrasound guidance improves patient survival (mortality) after drug-eluting stent implantation: review and updated bibliography

Individual studies IVUS vs angiography-guided DES implantation studies, whether randomized clinical trials or registries are underpowered, to show a reduction in mortality, especially at 1 year of follow-up. However, either meta-analyses or the few studies with long-term (> 5 year) follow-up showed that IVUS guidance reduced mortality and improved patient survival, even with second-generation DES.

Wire bias in coronary measurement using optical coherence tomography

OCT is widely used for accurate coronary stent sizing; however, the impact of coronary tortuosity or guide wire weight on the accuracy of OCT in assessing coronary dimensions is not known. This study sought to determine whether guide wire properties impact on coronary diameter and length estimation by optical coherence tomography (OCT) in tortuous segments of coronary artery. OCT coronary diameters were determined in selected patients with tortuous arteries before and after removal of a supportive guide wire to obtain unobscured images. In addition, a coronary model was created with lumen diameters of 1.7-4.8 mm. This was used to perform OCT images with a flexible (FW) and a stiff guide wire (SW) when straight or on a 25 mm radius curve to simulate tortuosity. Lumen diameter decreased by a mean of 3.2 + 1.0% after support wire removal in patients undergoing OCT for coronary sizing. In a coronary model, lumen length was constant when straight but underestimated between 0 and 4.5% (FW) and 0 and 12% (SW) when tortuous (P < 0.001, FW vs. SW, unpaired t test). Mean lumen diameter was overestimated by tortuosity (FW vs. SW for tube sizes 1.7 mm: +0-0.1 mm vs. +0.1-0.2 mm, P = 0.31; 2.7 mm: +0.02-0.17 mm vs. +0.18-0.46 mm, P < 0.01; 3.2 mm: +0.35-0.39 mm vs. +0.77-0.91 mm, P < 0.001; 4.8 mm: +0.4-0.69 mm vs. +0.88-1.05 mm, P < 0.001; unpaired t tests). Overestimation of diameter could be minimised by measuring luminal images with the least eccentric catheter position. OCT underestimation of length and overestimation of diameter should be considered when performing coronary intervention in tortuous vessels. The effect is augmented by increased wire stiffness.

Co-registration of angiography and intravascular ultrasound images through image-based device tracking

OBJECTIVES

To determine the feasibility of automated co-registration of angiography and intravascular ultrasound (IVUS) to facilitate integration of these two imaging modalities in a synchronous manner.

BACKGROUND

IVUS provides cross-sectional imaging of coronary arteries but lacks overview of the vascular territory provided by angiography. Co-registration of angiography and IVUS would increase utility of IVUS in the clinical setting.

METHODS

Forty-nine consecutive patients undergoing surveillance for cardiac allograft vasculopathy with angiography and IVUS of the left anterior descending artery (LAD) were enrolled. A pre-IVUS angiogram of the LAD was performed followed by an ECG-triggered fluoroscopy (ECGTF) during IVUS pullback at 0.5 mm/s using an automatic pullback device. ECGTF was used to track the IVUS catheter during pullback and establish a spatial relationship to the pre-IVUS angiogram. Angio-IVUS co-registration was performed with a research prototype (Siemens Healthcare, Germany) and accuracy was evaluated by distance mismatch between angiography and IVUS images at vessel bifurcations.

RESULTS

Median age was 54 (44.5, 67) years. The population was 82.6% male with minimal risk factors. The median (IQR) co-registration distance mismatch measured at 108 bifurcations in 42 (85%) patients was 0.35 (0.00-1.16) mm. Seven patients were excluded due to inappropriate data acquisition (n = 3) and failure of tracking (n = 4), e.g., due to overlapping sternal wires. Estimated effective radiation dose for ECGTF was 0.09 mSv.

CONCLUSION

This study demonstrates the feasibility of angio-IVUS co-registration which may be used as a clinical tool for localizing IVUS cross-sections along an angiographic roadmap. © 2015 Wiley Periodicals, Inc.