IVUS-Guided Stent Implantation to Improve Outcome: A Promise Waiting to be Fulfilled

The Ongoing Saga of the Evolution of Percutaneous Coronary Intervention: From Balloon Angioplasty to Recent Innovations to Future Prospects

The advances in percutaneous coronary intervention (PCI) have been, above all, dependent on the work of pioneers in surgery, radiology, and interventional cardiology. From Grüntzig's first balloon angioplasty, PCI has expanded through technology development, improved protocols, and dissemination of best-practice techniques. We can nowadays treat more complex lesions in higher-risk patients with favourable results. Guide wires, balloon types and profiles, debulking techniques such as atherectomy or lithotripsy, stents, and scaffolds all represent evolutions that have allowed us to tackle complex lesions such as an unprotected left main coronary artery, complex bifurcations, or chronic total occlusions. Best-practice PCI, including physiology assessment, imaging, and optimal lesion preparation are now the gold standard when performing PCI for sound indications, and new technologies such as intravascular lithotripsy for lesion preparation, or artificial intelligence, are innovations in the steps of 4 decades of pioneers to improve patient care in interventional cardiology. In the present review, major innovations in PCI since the first balloon angioplasty and also uncertainties and obstacles inherent to such medical advances are described.

TAVR prosthesis recoil: Unknowns and implications

TAVR acute recoil has not been properly assessed with current generation balloon-expandable prosthesis. Acute recoil was greater during initial deployment than in postdilatation, in middle stent than inflow or outflow, and in antero-posterior than lateral axis. No predictors or clinical implications of acute valvular recoil were detected, calling for further research to better understand this phenomenon.

Case Report: The Role of Intravascular Ultrasonography in Patients Underwent Percutaneous Coronary Intervention

Intravascular ultrasonography (IVUS) has an important role as a complimentary diagnostic tool in percutaneous coronary intervention procedure. IVUS provides valuable information regarding coronary vessel lumen and dimension and also plaque burden and its characteristic. The main use of IVUS in PCI is to guide the choose of interventional strategies to optimize stent deployment. Since drug eluting stent (DES) has promised to decrease the incidence in stent restenosis and stent thrombosis than bare metal stent, but neither the suboptimal results nor the complication after stenting with DES is still high. Thus, optimization of stent deployment under IVUS guidance is important in cases to decrease stent failure after PCI procedure, as well as to decrease complication rate after stenting in order to decrease mortality rate caused by coronary artery disease. We present here the use of IVUS guidance in a 43 and 46 year-old man underwent PCI.

Ex Vivo Assessment of Various Histological Differentiation in Human Carotid Plaque with Near-infrared Spectroscopy Using Multiple Wavelengths

We previously reported that near-infrared hyperspectral imaging enabled the localization of atherosclerotic plaques from outside the vessels, but not the optical characteristics of each histological component. Therefore, the near-infrared spectrum of each component was collected from the sliced section of the human carotid plaque obtained with endarterectomy and the optical characteristics were confirmed in several wavelengths. Based on this information, we assessed the diagnostic accuracy for ex vivo chemogram in each plaque component created with near-infrared spectroscopy (NIRS), using multiple wavelengths. The chemogram projected on the actual image of plaque was created based on light intensity and transmittance change at three wavelengths. The wavelengths that were mainly were 1440, 1620, 1730, and 1930 nm. We evaluated the accuracy of histological diagnosis in chemogram compared with pathological findings, analyzing interobserver agreement with κ-statistics. The chemograms that we created depicted the components of fibrous tissue, smooth muscle, lipid tissue, intraplaque hemorrhage, and calcification. Diagnostic odds ratio in each component was as follows: 259.6 in fibrous tissue, 144 in smooth muscle, 1123.5 in lipid tissue, 29.3 in intraplaque hemorrhage, and 136.3 in calcification. The κ-statistics revealed that four components, excluding intraplaque hemorrhage, had substantial or almost perfect agreement. Thus, this study demonstrated the feasibility of using chemogram focused on specific component during the histological assessment of atherosclerotic plaques, highlighting its potential diagnostic ability. Chemograms of various target components can be created by combining multiple wavelengths. This technology may prove to be useful in improving the histological assessment of plaque using NIRS.

Association between baseline platelet count and severe adverse outcomes following percutaneous coronary intervention

Objective

The aim is to evaluate the association between baseline platelet count (PC) and severe adverse outcomes following percutaneous coronary intervention (PCI) in current real-world practice.

Methods

A total of 18,788 patients underwent PCI with drug-eluting stents constituted the study population. Patients were categorized as having low (< 150 × 1000/µL), normal (150–300 × 1000/µL), and high (≥ 300 × 1000/µL) baseline PC. The primary endpoints included in-hospital and follow-up all-cause mortality. The secondary endpoint was major bleeding requiring a blood transfusion.

Results

In-hospital mortality rates for patients with low, normal, and high baseline PC were 0.6%, 0.4%, and 0.4%, respectively (P = 0.259). Similarly, mortality rates during long-term follow-up (median 23.8 months) for patients with low, normal, and high baseline PC were 0.9%, 0.6%, and 0.7%, respectively (P = 0.079). After multivariate adjustment, patients with low or high baseline PC tended to have similar risks for both in-hospital and follow-up mortality compared with the normal group. Subgroup analyses failed to demonstrate an independent prognostic value of baseline PC in specific population groups except patients who undwent transfemoral PCI. There was also no significant difference in the incidence of major bleeding requiring a blood transfusion in the low, normal, and high groups (0.5%, 0.3%, and 0.3%, respectively; P = 0.320). After multivariate adjustment, low or high baseline PC did not significantly increase the risk of major bleeding.

Conclusion

There is no significant association between baseline PC and severe adverse outcomes following PCI in current real-world practice.

Percutaneous Left Main Coronary Intervention: A Review of Plaque Modification in Left Main Percutaneous Coronary Intervention

Left main coronary artery (LMCA) stenosis has long been recognized as a marker of increased morbidity and mortality. Current treatment algorithms for LMCA stenosis consider both percutaneous coronary intervention (PCI) with drug eluting stents (DES) and coronary bypass surgery, each with advantages based on individual patient characteristics. Since the LMCA is the largest artery in the coronary tree, plaque volume and calcification is greater than other coronary segments and often extends to the distal bifurcation segment. In LMCA bifurcation lesions, larger minimal stent area is strongly associated with better outcome in the DES era. Plaque modification strategies such as rotational, orbital, or laser atherectomy are effective mechanisms to reduce plaque volume and alter compliance, facilitating stent delivery and stent expansion. We present a case of a calcified, medina class 1,1,1 LMCA lesion where intravascular ultrasound (IVUS) and orbital atherectomy were employed for optimal results. In this context, we review the evidence of plaque modification devices and the rationale for their use in unprotected left main PCI.

Expert Opinion: Optimising Stent Deployment in Contemporary Practice: The Role of Intracoronary Imaging and Non-compliant Balloons

Final stent dimensions remain an important predictor of restenosis, target vessel revascularisation (TVR) and subacute stent thrombosis (ST), even in the drug-eluting stent (DES) era. Stent balloons are usually semi-compliant and thus even high-pressure inflation may not achieve uniform or optimal stent expansion. Post-dilatation with non-compliant (NC) balloons after stent deployment has been shown to enhance stent expansion and could reduce TVR and ST. Based on supporting evidence and in the absence of large prospective randomised outcome-based trials, post-dilatation with an NC balloon to achieve optimal stent expansion and maximal luminal area is a logical technical recommendation, particularly in complex lesion subsets.

Direct oral anticoagulant use and stent thrombosis following an acute coronary syndrome: A potential new pharmacological option?

With the evolution of techniques and pharmacological strategies in percutaneous coronary intervention, significant advances have been made towards reducing the risk of in-stent restenosis and improving patient outcomes. However, in spite of these advances, stent thrombosis remains a deadly complication of stent implantation. The fundamental challenge in implementing a combined anticoagulant and antiplatelet strategy is balancing the risk of bleeding with the enhanced efficacy of therapy on both pathways. Results from the ATLAS ACS 2-TIMI 51 trial suggest that the addition of rivaroxaban 2.5mg twice daily to standard antiplatelet therapy may achieve this desired balance alongside careful patient selection. This review considers the clinical burden and pathology of stent thrombosis, oral antithrombotic strategies to reduce stent thrombosis, and what findings from recent trials could mean for the long-term management of patients with an acute coronary syndrome.

Understanding the economic impact of intravascular ultrasound (IVUS)

AIMS

To examine the cost-effectiveness of intravascular ultrasound (IVUS) use during percutaneous coronary intervention (PCI) with drug-eluting stents (DES) in treating coronary artery disease (CAD).

METHODS AND RESULTS

A Markov model was constructed with a lifetime horizon to compare costs and health outcomes between IVUS-guided PCI and PCI guided solely by angiography from an Italian healthcare payer perspective. The population examined included CAD patients undergoing PCI with DES. From a healthcare payer perspective, the resulting incremental cost-effectiveness ratio (ICER) per quality-adjusted life-year was negative in the base-case scenario (i.e., IVUS benefit assumed to persist beyond the first year). When IVUS benefit was assumed to be limited to the first year, the ICER increased to €9,624. This conclusion remained consistent even when scenarios varied regarding the duration of the device's effect. Furthermore, benefits of using IVUS were greater for patients with acute coronary syndrome, renal insufficiency, and diabetes.

CONCLUSIONS

Using IVUS with angiography is a dominant strategy in Italy, and results demonstrate that it is desirable to target those at a greater risk of restenosis (i.e., patients with diabetes, chronic kidney disease, and acute coronary syndrome), who tend to benefit more from accurate stent implantation. Further information is necessary regarding the long-term benefits of IVUS, however sensitivity analysis presented in this research demonstrates a strong argument supporting the cost-effectiveness of IVUS.

Is postdilatation with a noncompliant balloon necessary after coronary stent deployment during primary angioplasty?

BACKGROUND

Postdilatation (PD) with noncompliant balloon during elective percutaneous coronary intervention (PCI) is performed usually in clinical practice in order to optimize stent expansion. However, current knowledge about its use in patients undergoing primary PCI is controversial. This study aims to evaluate the angiographical and clinical results of PD in patients who underwent primary PCI with drug eluting stents (DESs).

METHODS

A total of 405 consecutive patients (mean age 56.9 ± 12.3 years; 302 male) with ST elevation myocardial infarction were evaluated retrospectively. Patients received DES with or without predilatation according to physician's discretion. Eligible patients were divided into 2 groups based on PD procedure. The clinical end-points were death, target vessel revascularization (TVR) and stent thrombosis at 6 months after PCI. The angiographic end-points were postprocedural correct Thrombolysis in Myocardial Infarction (TIMI) frame count (cTFC), final TIMI flow, and myocardial blush grade (MBG).

RESULTS

PD was performed in 214 patients (52.8%). Angiographical parameters such as TIMI flow, cTFC, and MBG did not differ after PD (P>0.05). During 6-month follow-up, TVR and stent thrombosis rates were lower in the PD group (6 vs. 16, P=0.03; and 3 vs. 10, P=0.04, respectively). PD and diabetes were detected as independent predictors of MACE (β=0.52, P=0.01, and β=-0.47, P=0.02; respectively).

CONCLUSION

Our study revealed that PD does not yield adverse effects on final angiographic parameters when performed during primary PCI. Besides PD seems to decrease probability of stent thrombosis and TVR.

Overaggressive stent expansion without intravascular imaging: impact on restenosis

OBJECTIVE

Aggressive stent expansion is required for optimal strut apposition, but risk of stent deformation, fracture and subsequent restenosis is potentially greater when performed without intravascular imaging guidance. We investigated how frequently stents are 'overexpanded' and whether this correlates with restenosis.

DESIGN AND SETTING

Single-centre prospective database study at a high-volume tertiary university hospital.

PATIENTS

243 patients undergoing single-vessel stenting for de novo stenosis in 277 lesions. Exclusion criteria were bifurcational, graft or left main disease and intravascular imaging use. All had ischaemia-driven repeat coronary angiography up to 48 months later. Degree of stent overexpansion was the difference between nominal and final stent size.

RESULTS

Stents were expanded above nominal in 99% of cases and above rated burst pressure in 52%. Stents were expanded >20% above nominal in 12% of cases. Stents overexpanded by >20% were smaller (2.87 vs 3.19 mm), longer (24 vs 19 mm) and more often drug-eluting (53% vs 27%). Angiographic restenosis was observed in 80 lesions (29%). There was no correlation between degree of overexpansion and per cent angiographic restenosis across the whole group (R(2)=-0.01; p=0.09), in those with stent overexpansion >20% (p=0.31) or small stents <3 mm (p=0.71). Indeed, in the group with stent overexpansion >25%, the greater the overexpansion, the less the per cent angiographic restenosis (p=0.02).

CONCLUSIONS

In this real-world population undergoing non-complex percutaneous coronary intervention without intravascular imaging, any tendency to overaggressive stent expansion did not predispose at all to restenosis.

Long-term safety of drug-eluting stents

Stent implantation in coronary stenosis has revolutionized the treatment of coronary artery disease. The introduction of antirestenotic drug coatings further improved their efficacy in reducing target vessel revascularizations. With increasing use of drug-eluting stents (DES), stent thrombosis (ST) rose as potentially fatal major complication. Initially, the incidence of ST late after stent implantation seemed to be similar for DES and bare metal stents until several studies proved otherwise in first-generation DES. Since then, the design and components of DES have been changed and new polymers, drugs and different combinations of platelet inhibitors have been introduced to further improve the safety of DES. In this review, the authors focus on the relationship between DES, lesion anatomy, implantation technique and pharmacology to avoid the occurrence of ST. Furthermore, the relationship between dual antiplatelet therapy, bleeding rate and its significant impact on patient outcome is discussed. Finally, some promising future concepts are highlighted.

Comparison of Two Different Strategies of Intravascular Ultrasound Guidance during Percutaneous Coronary Intervention; Routine versus Selective

BACKGROUND AND OBJECTIVES

Intravascular ultrasound (IVUS) is helpful during percutaneous coronary intervention (PCI), because it can be used to confirm good apposition or optimal expansion of stents. In this study, we compared angiographic result as well as clinical outcomes between two different strategies of IVUS-guidance, the selective vs. the routine.

SUBJECTS AND METHODS

The study population consisted of 279 patients undergoing electric and emergency intracoronary implatation of TAXUS stent from August 2003 through September 2006. For this study, we divided physicians into two groups; doctors to perform PCI under 'routine' IVUS-guidance vs. PCI under 'selective' IVUS-guidance. Among a total of 279 patients (384 lesions) who underwent PCI with TAXUS stent, 87 patients underwent the procedure under the strategy of 'routine' IVUS-guidance, whereas 192 patients under 'selective' IVUS-guidance.

RESULTS

The baseline clinical features of the patients are similar between the two groups. The actual rate of IVUS usage was 89.2% in the routine group and 68.2% in the selective group (p<0.01). A high rate of adjunctive ballooning was determined as a remarkable procedure-related parameter which was comparable between the two groups (72.5% vs. 76.1% in routine vs. selective, p=0.57). The minimal lumen diameter at immediate post-PCI was significantly larger in the routine IVUS group than that in the selective group (2.58 mm vs. 2.48 mm, p=0.03). However, the difference disappeared during the follow-up period (1.98 mm vs. 1.98 mm, p=0.94). Clinical outcomes at 1 year were not different between the two groups.

CONCLUSION

PCI under the strategy of 'selective' IVUS-guidance was comparable to PCI under 'routine' IVUS-guidance in terms of angiographic and clinical outcomes in circumstances with frequent use of adjunctive ballooning after stenting.

Long-term outcomes with use of intravascular ultrasound for the treatment of coronary bifurcation lesions

Percutaneous coronary intervention (PCI) of bifurcation lesions remains challenging with a higher risk of adverse outcomes. Whether adjunctive intravascular ultrasound (IVUS) imaging improves outcomes of PCI of bifurcation lesions remains unclear. This study sought to determine the long-term clinical outcomes associated with using IVUS for percutaneous treatment of coronary bifurcation lesions. From April 2003 through August 2010, 449 patients with 471 bifurcation lesions underwent PCI with (n = 247) and without (n = 202) the use of IVUS. Clinical outcomes (death, myocardial infarction [MI], periprocedural MI, stent thrombosis, target vessel revascularization [TVR], and target lesion revascularization [TLR]) were compared between patients undergoing PCI with and without IVUS using univariate and propensity score-adjusted analyses. Most patients (61%) presented with acute coronary syndrome and 89% of bifurcations lesions were Medina class 1,1,1. After propensity score adjustment, use of IVUS was associated with significantly lower rates of death or MI (odds ratio 0.38, 95% confidence interval 0.20 to 0.74, p = 0.005), death (odds ratio 0.40, 95% confidence interval 0.18 to 0.88, p = 0.02), MI (odds ratio 0.37, 95% confidence interval 0.14 to 0.98, p = 0.04), periprocedural MI (odds ratio 0.45, 95% confidence interval 0.20 to 0.97, p = 0.04), TVR (odds ratio 0.28, 95% confidence interval 0.14 to 0.53, p <0.0001), and TLR (odds ratio 0.27, 95% confidence interval 0.14 to 0.53, p = 0.0003) compared to no IVUS. In conclusion, IVUS-guided treatment of complex bifurcation lesions was associated with significantly lower rates of adverse cardiac events at late follow-up. Further study is warranted to evaluate the role of IVUS guidance in improving long-term outcomes after PCI of bifurcation lesions.

Impact of frequency-domain optical coherence tomography guidance for optimal coronary stent implantation in comparison with intravascular ultrasound guidance

BACKGROUND

Frequency-domain optical coherence tomography (FD-OCT) is a novel, high resolution intravascular imaging modality. Intravascular ultrasound (IVUS) is a widely used conventional imaging modality for achieving optimal stent deployment. The aim of this study was to evaluate the impact of FD-OCT guidance for coronary stent implantation compared with IVUS guidance.

METHODS AND RESULTS

A total of 70 patients with de novo coronary artery lesions and either unstable or stable angina pectoris were enrolled in this randomized study (optical coherence tomography [OCT] group: n=35, IVUS group: n=35). In the OCT group, stent implantation was performed under FD-OCT guidance alone and final stent expansion was evaluated by IVUS. In the IVUS group, conventional IVUS guidance was used and final stent apposition was evaluated by FD-OCT. There were no significant differences regarding the procedural, fluoroscopy time, and contrast volume. Although device and clinical success rates also were similar, the visibility of vessel border was significantly lower in the OCT group (P<0.05). Minimum and mean stent area and focal and diffuse stent expansion were smaller (6.1±2.2 mm versus 7.1±2.1 mm, 7.5±2.5 versus 8.7±2.4 mm, 64.7±13.7% versus 80.3±13.4%, 84.2±15.8% versus 98.8±16.5%, P<0.05, respectively), and the frequency of significant residual reference segment stenosis at the proximal edge was higher in the OCT group (P<0.05). Incomplete apposed struts in both groups were similar (P=0.34).

CONCLUSIONS

FD-OCT guidance for stent implantation was associated with smaller stent expansion and more frequent significant residual reference segment stenosis compared with conventional IVUS guidance.

Comparison of haemodialysis patients and non-haemodialysis patients with respect to clinical characteristics and 3-year clinical outcomes after sirolimus-eluting stent implantation: insights from the Japan multi-centre post-marketing surveillance registry

AIMS

Long-term outcomes after sirolimus-eluting stent (SES) implantation in haemodialysis (HD) patients have remained controversial. We investigated the impact of HD on outcomes after SES implantation.

METHODS AND RESULTS

We analysed the data on 2050 patients who underwent SES implantation in a multi-centre prospective registry in Japan. Three-year clinical outcomes were compared between the HD group (n = 106) and the non-haemodialysis (NH) group (n = 1944). At the 3-year clinical follow-up, the rates of unadjusted cardiac mortality (HD: 16.3 vs. NH: 2.3%) and target-lesion revascularization (TLR) (HD: 19.4 vs. NH: 6.6%) were significantly higher in the HD group than the NH group (P < 0.001). Although HD group had a numerically higher stent thrombosis rate, the difference in stent thrombosis between the two groups (HD: 2.0 vs. NH: 0.7%) did not reach statistical significance. Using Cox's proportional-hazard models with propensity score adjustment for baseline differences, the HD group had higher risks of TLR [HD: 16.3 vs. NH: 6.1%; hazard ratio, 2.83; 95% confidence interval (CI): 1.62-4.93, P = 0.0003] and cardiac death (HD: 12.3 vs. NH: 2.3%; hazard ratio, 5.51; 95% CI: 2.58-11.78, P < 0.0001). The consistent results of analyses, whether unadjusted or adjusted for other baseline clinical and procedural differences, identify HD as an independent risk factor for cardiac death and TLR.

CONCLUSIONS

Percutaneous coronary intervention with SES in HD patients has a higher incidence of repeat revascularization and mortality compared with those in NH patients. Haemodialysis appears to be strongly associated with mortality and repeat revascularization even after SES implantation.