Shigeru Saito MD, FACC, FSCAI.

As everybody can agree, chronic total occlusion (CTO) lesion is the lesion subset remaining in the last frontier for percutaneous coronary intervention (PCI). Because of the difficulty in randomization, we cannot have enough evidence for the clinical significance of successful recanalization of these lesions by PCI. However, PCI in CTO lesions has been attracting many enthusiastic operators, and they have been developing new devices and PCI techniques. In Japan, people traditionally do not like to have open heart surgery. This custom, in addition to the late development of coronary bypass surgery, has promoted the development of PCI techniques by many enthusiastic operators. I would propose that the progress in PCI for CTO lesions could be divided into the following arbitrary four phases.

THE DRAWN OF PCI FOR CTO LESIONS

1. TOP OF PAGE
2. THE DRAWN OF PCI FOR CTO LESIONS
3. MAJOR CONTRIBUTIONS OF JAPANESE INTERVENTIONAL CARDIOLOGISTS
4. DEVELOPMENT OF NEW DEVICES
5. INTRODUCTION OF BI-DIRECTIONAL (RETROGRADE) APPROACH
6. REFERENCES

PCI was initiated using “on-the-wire” balloon system by its inventor, Andreas Gruentzig, in 1977. The introduction of “over-the-wire” balloon system by Simpson and Robert (Simpson-Robert's balloon) in 1982 promoted the development of various types of PCI guidewires and developed the new concept that we could exchange various kinds of PCI guidewires during PCI. The initial attempts to open the chronic total occlusion were performed with the introduction of concomitant use of thrombolytic agents and simultaneous bilateral coronary angiography. However, the success rate for CTO lesions was less than 70% those days.

MAJOR CONTRIBUTIONS OF JAPANESE INTERVENTIONAL CARDIOLOGISTS

1. TOP OF PAGE
2. THE DRAWN OF PCI FOR CTO LESIONS
3. MAJOR CONTRIBUTIONS OF JAPANESE INTERVENTIONAL CARDIOLOGISTS
4. DEVELOPMENT OF NEW DEVICES
5. INTRODUCTION OF BI-DIRECTIONAL (RETROGRADE) APPROACH
6. REFERENCES

The Development of Guidewires Designed for CTO Lesions Several guidewires with different tip stiffness were developed in early 90s by Japanese Interventional Cardiologists and companies. The introduction of these guidewires improved the success rate more than 80%. Pathological examination of the CTO lesions revealed the presence of micro vascular channels within the lesions, which could not be visualized by fluoroscopy. This findings lead to the development of tapered-tip guidewires and improved the success rate of PCI.

The Development of Adjunctive Techniques
After the acquisition of new CTO guidewires, many physicians has been developing different kinds of adjunctive techniques including “double guidewire technique”, “side-branch technique”, “IVUS-guided technique”, “anchoring-balloon technique”, or “the use of child guiding catheters”.

The success rate reached 90% by the introduction of new guidewires and adjunctive techniques.

DEVELOPMENT OF NEW DEVICES

1. TOP OF PAGE
2. THE DRAWN OF PCI FOR CTO LESIONS
3. MAJOR CONTRIBUTIONS OF JAPANESE INTERVENTIONAL CARDIOLOGISTS
4. DEVELOPMENT OF NEW DEVICES
5. INTRODUCTION OF BI-DIRECTIONAL (RETROGRADE) APPROACH
6. REFERENCES

From early 2000s, several new devices have been developed. These include excimer laser angioplasty, ultrasound angioplasty, radiofrequency angioplasty, cryoablation angioplasty and so on. However, these new devices could not improve the success rate efficiently.

INTRODUCTION OF BI-DIRECTIONAL (RETROGRADE) APPROACH

1. TOP OF PAGE
2. THE DRAWN OF PCI FOR CTO LESIONS
3. MAJOR CONTRIBUTIONS OF JAPANESE INTERVENTIONAL CARDIOLOGISTS
4. DEVELOPMENT OF NEW DEVICES
5. INTRODUCTION OF BI-DIRECTIONAL (RETROGRADE) APPROACH
6. REFERENCES

Bidirectional approach through the collateral channels was developed around 2004 in Japan. This technique has been continuously improved. In this journal, Suzuki et al. introduced the newest version of this approach. I am very much encouraged to know that still we can improve the success rate of PCI for CTO lesion

Catheterization and Cardiovascular Interventions, Volume 76, Issue 4, pages 541–542. Editorial Comment.