Safety and feasibility of a low frame rate protocol for percutaneous coronary intervention to chronic total occlusions: preliminary experience

PET evaluation of myocardial perfusion function after percutaneous coronary intervention in patients with chronic total occlusion: a systematic review and meta-analysis

Objective. The benefit of percutaneous coronary intervention (PCI) in chronic complete coronary artery occlusion (CTO) remains controversial. PCI is currently indicated only for symptom and myocardial ischemia abolition, but large chronically occluded vessels with extensive afferent myocardial territories may benefit most from this procedure. The noninvasive evaluation of myocardial perfusion is critical before and after revascularization, and positron emission tomography (PET) can determine absolute myocardial perfusion. Here, we aimed to explore and compare myocardial perfusion in CTO territories and their remote associated areas before and after PCI. Design. We searched for relevant articles published before November 28, 2022, in the Cochrane Library and PubMed. We calculated 95% confidence intervals (CIs) and standardized mean differences (SMDs) for parameters related to myocardial perfusion in CTO territories and remote areas in CTO patients before and after PCI. Results. We included five studies published between 2017 and 2022, with a total of 592 patients. Stress myocardial blood flow (MBF) was increased in CTO territories after PCI when compared to pre-PCI (mean difference [MD]: 1.70, 95% confidence interval [CI] 1.33-2.08, p < 0.001). Coronary flow reserve (CFR) in CTO regions was also higher after PCI (MD 1.37,95% [CI]1.13-1.61, p < 0.001). Stress MBF in remote regions was also increased after PCI (MD 0.27,95% [CI]0.99 ∼ 0.45, p = 0.004), as was CFR in remote regions (MD 0.32,95% [CI] 0.14-0.5, p = 0.001). Conclusions. According to our pooled analysis of current literature, there was an increase in stress MBF and CFR in both CTOs and remote regions after PCI, suggesting that patients with CTO have widespread recovery of blood perfusion after the procedure. These results provide evidence that patients with CTO arteries and high ischemic burdens would indeed benefit from CTO-PCI. Future research on the correlation of ischemia burden reduction with hard clinical endpoints would contribute to a clearer demarcation of the role of CTO PCI with prognostic potential.

Retrograde Approach via Ipsilateral Septal Collateral Channel in Percutaneous Coronary Intervention for Coronary Chronic Total Occlusion: A Single-Center Experience

Background

The septal collateral channel (CC) is the preferred channel in retrograde percutaneous coronary intervention (PCI) for chronic total occlusion (CTO). However, reports on the utilization of the ipsilateral septal CC are limited.

Objective

To evaluate the feasibility and safety of the ipsilateral septal CC in retrograde CTO PCI.

Methods

Twenty-five patients with successful wire CC tracking via the ipsilateral septal CC in retrograde CTO PCI were retrospectively analyzed. All procedures were performed by experienced CTO operators. Procedures were divided into the left descending coronary artery (LAD)-septal-LAD group and the LAD-septal-left circumflex coronary artery (LCX) group. Procedural complications and in-hospital outcomes were ascertained.

Results

Both groups were similar with respect to risk factors and angiographic characteristics of the CTO, except for the collateral tortuosity (86.7% vs 20%, p=0.002). The success rate of microcatheter CC tracking was 96%. Both technical success and procedural success rates were 92%. Procedural complications were found in one case (septal perforation, 4%), which happened in the LAD-septal-LAD group (p=0.250). One postoperative adverse event (Q-wave myocardial infarction, 4%) was observed before discharge.

Conclusion

The retrograde approach via the ipsilateral septal CC was feasible, with high success rates and acceptable complications, in the hands of experienced operators.

Reducing fluoroscopic and cineangiographic contribution to radiation exposure for chronic total coronary occlusion interventions

BACKGROUND

The treatment of chronic total coronary occlusions (CTO) carries the highest radiation exposure among percutaneous coronary interventions (PCI). In order to minimize radiation damage, we need to understand and optimize the contribution of all components of radiation exposure.

METHODS

A total of 1000 CTO procedures performed between 2011 and 2020 were compared according to implemented radiation modifications. Group 1 used the original set-up of the X-ray equipment (Artis Zee, Siemens). In group 2 a modified protocol aimed at reducing the fluoroscopy exposure, in group 3 further modifications aimed at reducing cineangiographic exposure.

RESULTS

Despite an increased lesion complexity, Air Kerma (AK) was reduced from 2619 mGy (1653-4574) in group 1 to 2178 mGy (1332-3500; p < 0.001) in group 2 by mainly reducing fluoroscopic contribution by 54.1%, the cineangiographic contribution was lowered by only 6.6%. In group 3 AK dropped drastically to 746 mGy (480-1225; p < 0.001) mainly by reducing the cineangiographic contribution by 53.4%, still there was a further reduction of fluoroscopy contribution of 8.2%. This also led to a reduction of the skin entry dose from 1038 mGy (690-1589) in group 2 to 359 mGy (204-591; p < 0.001) in group 3. This was achieved both in normal weight and obese patients, and both in antegrade and retrograde procedures.

CONCLUSIONS

The present study demonstrates that by modifying both the fluoroscopic and cineangiographic contribution to radiation exposure a drastic reduction of radiation risk can be achieved, even in obese patients. Currently accepted radiation thresholds may no longer be a limit for CTO PCI.

Latest developments in chronic total occlusion percutaneous coronary intervention

INTRODUCTION

Chronic Total Occlusion Percutaneous Coronary Intervention (CTO PCI) is now performed with high success rates and acceptable complication rates.

AREAS COVERED

We describe recent clinical and technological developments in CTO PCI from 2018 to 2020.

EXPERT OPINION

After publication of six randomized controlled trials, improving patient symptoms remains the principal indication for CTO PCI. Although good outcomes can be achieved with CTO PCI at experienced centers, success rates are significantly lower at less experienced centers, despite increased use in CTO crossing algorithms and development of novel and improved equipment and techniques.

Determinants of Greater Peak radiation skin dose in percutaneous coronary intervention for chronic total occlusion

BACKGROUND

Peak skin dose (PSD) is closely associated with skin radiation injuries such as skin ulcers in percutaneous coronary intervention (PCI). Although PSD is greater in PCI for chronic total occlusion (CTO) lesions as compared with non-CTO lesions, the determinants of PSD in CTO-PCI are not fully understood. The purpose of this study was to investigate the clinical factors associated with excess PSD in PCI for CTO.

METHODS

The study population included a total of 220 CTO-PCI cases that were divided into a standard PSD group (<2 Gy, n = 187) and an excess PSD group (≥2 Gy, n = 33). Clinical, lesion, and procedural characters were compared between the 2 groups. Multivariate logistic regression was performed to investigate the clinical factors associated with excess PSD.

RESULTS

Body surface area (BSA) was significantly higher in the excess PSD group (1.85 ± 0.24 m²) than the standard PSD group (1.71 ± 0.18 m²) (p = 0.001). The J-CTO score was significantly higher in the excess PSD group (2.51 ± 1.28) than the standard PSD group (1.60 ± 1.13) (p < 0.001). Multivariate logistic regression analysis revealed that BSA (0.1 mm increase: OR 1.663, 95% CI 1.300-2.128, p < 0.001) and J-CTO score (1-point increase: OR 2.015, 95% CI 1.322-3.071, p = 0.001) were significantly associated with excess PSD.

CONCLUSIONS

A large BSA and high J-CTO score were significantly associated with excess PSD. It is important to pay special attention to CTO patients who have a large BSA and/or high J-CTO score to reduce patient's PSD.

Utilization of an Optimized Radiation Strategy in Primary Percutaneous Coronary Intervention for Patients with ST-Segment-Elevation Myocardial Infarction

Background

Recent reports about radiation risk gradually raised the safety concerns for interventional therapy. However, limited data exist on the optimized radiation strategy in primary percutaneous coronary intervention (P-PCI) for patients with ST-segment-elevation myocardial infarction (STEMI).

Methods

A total of 214 STEMI patients undergoing P-PCI were retrospectively analyzed. Patients were divided into the optimized radiation strategy (ORS) group (N = 151) and normal radiation strategy (NRS) group (N = 63) according to the radiation protocol utilized. The primary endpoint was the relative dose reduction of total air kerma. The secondary endpoint was 30-day major adverse cardiac and cerebrovascular events (MACCE), as a composite of all-cause death, reinfarction, ischemia-driven target vessel revascularization, and stroke.

Results

Patient groups were well matched for baseline characteristics. There were no differences in terms of age, body mass index, radial artery access, nonculprit vessel PCI, and fluoroscopy time between 2 groups. With optimized radiation strategy, a 40.9% radiation dose reduction (901.2 ± 628.7 mGy versus 1524.0 ± 866.6 mGy, p < 0.001) was obtained for total air kerma. No significant differences were found for 30-day MACCE between 2 groups (2.0% versus 1.6%, adjusted hazard ratio: 0.7, 95% confidence interval: 0.1 to 8.6, p=0.772).

Conclusion

With optimized radiation strategy, significant radiation dose reduction could be achieved in P-PCI for STEMI patients. It appears to be feasible and safe to carry out the optimized radiation strategy in P-PCI for STEMI patients.

Contemporary Approach to Chronic Total Occlusion Interventions

PURPOSE OF REVIEW

Chronic total occlusion (CTO) poses one of the greatest technical challenges to interventional cardiologists. Despite recent advancements in techniques and clinical trials showing significant benefits of CTO percutaneous coronary interventions (PCI), the proportion of patients with untreated CTOs remains high. We therefore aim to perform a comprehensive review of the various techniques available, recent advancements, benefits, and complications associated with CTO PCI.

RECENT FINDINGS

Three randomized clinical trials examining the benefits of CTO PCI have recently been presented. Scoring systems have been developed to facilitate pre-procedural estimation of success and complications of CTO PCI. Technological enhancements in coronary wires and other interventional equipment along with dedicated training for CTO operators have improved the likelihood of successful recanalization of CTOs. CTO PCI has been shown to improve patient symptoms and quality of life. It is therefore important to have an in-depth knowledge of the various CTO techniques, appropriate equipment, and complications when performing these complex procedures. Clinicians should weigh the risks and benefits and choose the appropriate patient population who may benefit from revascularization.

A propensity score matched valuation on feasibility of low frame rate fluoroscopy during primary percutaneous coronary intervention for patients with STEMI

The present study aimed to evaluate the feasibility of low frame rate fluoroscopy during primary percutaneous coronary intervention (PPCI) for patients with acute ST elevation myocardial infarction (STEMI). From January 2016 to December 2017, 165 consecutive patients with STEMI who underwent PPCI were retrospectively divided into two groups: the 7.5-frame group (fluoroscopy at 7.5 frames/s) and the 15-frame group (fluoroscopy at 15 frames/s), according to the frame rate of fluoroscopy used in their treatment. Reduction of radiation and safety of fluoroscopy at 7.5 frames/s were compared by a method of propensity score matching (PSM) with fluoroscopy at 15 frames/s. After PSM, there were 56 patients in each group. There were no differences in patients' baseline characteristics between two groups. The 7.5-frame protocol resulted in 48.9% reduction of DAP (9917 ± 5543 cGycm² vs. 14766 ± 7272 cGycm², P < 0.001) and 61.1% reduction of AK (1209 ± 562 mGy vs. 1948 ± 1105 mGy, P < 0.001) with comparable procedural time (38.1 ± 15.3 min vs. 38.8 ± 17.2 min, P = 0.830), fluoroscopy time (13.0 ± 7.2 min vs. 13.5 ± 8.1 min, P = 0.703) and contrast volume (122.3 ± 39.4 ml vs. 119.3 ± 49.4 ml, P = 0.725) to the 15-frame group. Meanwhile, this new protocol didn't increase the incidence of contrast-induced nephropathy (23.2% vs. 25.0%, OR = 0.907, 95% CI 0.381-2.157, P = 0.825) and peri-PPCI cumulative adverse events (30.4% vs. 28.6%, OR = 1.090, 95% CI 0.483-2.456, P = 0.836). In conclusion, low frame rate fluoroscopy at 7.5 frames/s is a safe and feasible strategy for reducing radiation during PPCI.