“Seesaw Balloon-Wire Cutting” Technique as a Novel Approach to “Balloon Uncrossable” Chronic Total Occlusions

Abstract: Background. Balloon crossing failure after passing a guidewire usually leads to unsuccessful percutaneous recanalization of chronic total occlusions (CTOs). We sought to investigate a novel technique for solving this problem. Methods. Twenty-one patients with failed balloon crossing through CTOs after successful guidewire passing were treated with the “seesaw balloon-wire cutting” technique between July 2012 and May 2013. The main process of this technique was to insert two guidewires (guidewire A and guidewire B) into the distal true lumen of CTOs and then to advance two short and low-profile balloons (balloon A and balloon B) over the two guidewires, respectively. Balloon A was first advanced over guidewire A as distally as possible, and then was inflated with high pressure (≥18 atm) to press guidewire B, producing a cutting power to crush the proximal fibrous cap of the CTO. Subsequently, balloon A was withdrawn slightly, and balloon B was advanced as distally as possible and then was inflated to press guidewire A, producing a similar cutting effect to crush the proximal fibrous cap on the other side. The two balloons were progressed alternatively until one of them was able to cross through the occluded segment. Results. This new technique was successfully applied in 17 patients (81.0%), leading to procedural success of their CTOs. The technique failed in 4 patients (19.0%) due to heavy calcification. No complications occurred in all patients. Conclusion. The seesaw balloon-wire cutting technique is an effective and safe approach to facilitate balloon crossing during CTO interventions.   

J INVASIVE CARDIOL 2014;26(4):167-170

Key words: CTO intervention, calcification

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Percutaneous coronary intervention (PCI) for chronic total occlusions (CTOs) represents one of the “last frontiers” in interventional cardiology. Despite the expertise of operators and the development of novel interventional techniques and devices, the procedural success rate of CTOs remains significantly lower than in non-occluded lesions. The greatest challenge of CTO recanalization is to cross guidewires and balloons through the occluded segment.¹ Although the CTO-dedicated guidewires have improved the success rate of guidewire crossing, the subsequent balloon passage through the occlusion is still difficult under some circumstances, which usually leads to procedural failure of CTO recanalization.^2,3 Recently, a number of techniques and devices have been introduced to facilitate balloon crossing through CTOs, including the use of more supportive guiding catheters, “child-in-mother” guide system, anchor balloon technique, Tornus catheter, excimer laser, and rotational atherectomy.^3-9 However, complex manipulation, expensive cost, and availability limit the application of these methods. Therefore, we attempted to invent an easy, low-cost, and more effective technique for facilitating balloon passage through CTOs. 

Methods

Patients and PCI procedure. Between July 2012 and May 2013, a total of 105 patients with CTO lesions in native coronary arteries underwent PCI in our catheterization laboratory. The indication of PCI was the presence of symptomatic angina or documented silent myocardial ischemia. PCI was performed according to standard clinical protocol. Routine dosages of aspirin and clopidogrel were given to all patients before and after the procedure. Unfractionated heparin was administered intravenously to achieve a target activated clotting time of 250 seconds. Transradial approach was chosen in most patients. Guiding catheters like EBU, Heartrail BL, or Amplatz were often used to provide better support. Intraluminal location of the distal tip of the guidewire was confirmed in multiple views by contrast filling the distal bed via contralateral or ipsilateral injection. Drug-eluting stents were implanted after balloon predilation. During the PCI procedure, twenty-one out of 105 patients had unsuccessful attempts of crossing the occluded lesion with the available lowest-profile balloon following successful guidewire passage. Initially, we tried the multiwire crushing technique⁹ in most patients and the anchor balloon technique in 5 patients, but they all failed. Therefore, we applied the “seesaw balloon-wire cutting” technique in these patients. The main process of the novel technique consisted of the following steps: a guidewire (guidewire A) was first inserted into the distal true lumen of CTOs, and then another stiffer hydrophilic guidewire (guidewire B) was slowly manipulated to cross the occluded segment along with guidewire A; two short and low-profile balloons (balloon A and balloon B, chosen from 1.2 × 6 mm MiniTREK, Abbott; 1.25 × 6 mm Sprinter Legend, Medtronic; or 1.25 × 10 mm Tazuna, Terumo) were advanced over the two guidewires, respectively; balloon A was first advanced over guidewire A as distally as possible, and then the balloon was inflated with high pressure (≥18 atm) to press guidewire B, producing a cutting power to crush the proximal fibrous cap of the CTOs. Subsequently, balloon A was withdrawn slightly, and balloon B was advanced as distally as possible and then was inflated to press guidewire A, producing a similar cutting effect to crush the proximal fibrous cap on the other side; the two balloons were progressed alternatively until one of them was able to cross through the occluded segment (Figure 1). 

Definitions. A chronic total occlusion was defined as a lesion exhibiting thrombolysis in myocardial infarction (TIMI) flow grade 0 or grade 1 with duration of ≥3 months. The duration of coronary occlusion was estimated from clinical events including myocardial infarction, sudden onset or worsening of the symptoms that were consistent with the occlusion location, or proved by previous coronary angiography. Technique success was defined as the balloon crossing through CTOs successfully after the seesaw balloon-wire cutting procedure. PCI success was defined as the restoration of TIMI flow grade 3 with a residual stenosis of <20% in target CTOs after stent implantation.

Statistical analyses. Continuous parameters were presented as mean ± standard deviation. Discrete parameters were reported as percentages. All analyses were performed using SPSS 19.0.

Results

Clinical and angiographic characteristics. Clinical characteristics of all patients are summarized in Table 1. More patients were males, smokers, or had stable angina. Almost half of the patients were diabetic, hypertensive, or hyperlipidemic. About one-third of patients had prior myocardial infarction and 3 patients underwent a prior failed CTO PCI at local hospitals. Angiographic characteristics of all patients are presented in Table 2. There was a total of 21 target CTOs in 21 main vessels and one-third of the patients had diffuse triple-vessel disease. All vessels with a target CTO had collaterals supplying the distal vessel, including bridging, contralateral and/or ipsilateral circulation. 

Technique features and procedural outcomes. Technique features and procedural outcomes are shown in Table 3. The seesaw balloon-wire cutting technique was successfully performed in 17 patients (81.0%), leading to procedural success of their CTO lesions. The technique failed in 4 patients (19.0%) due to heavy circular calcification. Three of them had difficulty crossing a balloon through the lesion and 1 procedure was problematic while placing the second guidewire into the distal true lumen. As a bail-out procedure, a Rotablator was attempted in the 4 patients; 3 of these succeeded and 1 failed while exchanging the guidewire to the RotaWire. Hydrophilic stiff wires were selected as the second guidewire in 21 patients. The mean time of the successful seesaw balloon-wire cutting procedure was relatively short (21.9 ± 6.6 minutes). Total amount of contrast medium used during the PCI procedure was 256.7 ± 75.8 mL (range, 120-380 mL). No serious complications (coronary dissection, perforation, or death) were observed. Two cases of successful application of the seesaw balloon-wire cutting technique were illustrated in Figure 2.

Discussion

Previous studies have shown that the inability of the balloon to cross the wired occlusion accounts for 2%-9% of failed CTO recanalization procedures.^1,2 The main factors contributing to this scenario include heavy calcification within the CTO lesions and severe coronary tortuosity. To overcome the frustrating situation, several techniques and devices have been invented in recent years.^3-9 While the effects of these methods have been proven, their availability, complexity, potential risks, and cost have to be taken into consideration in clinical practice. For example, techniques involving the exchange of a more supportive guiding catheter may have a risk of losing the position of the original passed guidewire; the anchor balloon technique requires a proper side branch and has the potential hazard of injuring the side branch; the “child-in-mother” catheter provides more support by deep intubation of the child catheter, which may damage the vessel. In addition, the use of rotational atherectomy is limited by the necessity of recrossing the occlusion with the dedicated and less maneuverable 0.009˝ stainless-steel RotaWire. This exchange procedure is not always successful if no microcatheter crosses through the lesion. The Tornus device has been proposed as a very effective strategy for the present scenario; however, it must be emphasized that complications such as perforation and procedure-related myocardial infarction may occur as a consequence of Tornus manipulation.¹⁰ Recently, the “wire-cutting” technique has appeared to be a promising approach for facilitating balloon passage.³ However, the ostium of the coronary artery is likely to be injured by the tip of the guiding catheter during the wire-cutting procedure while pulling back the pressed guidewire. 

The initial results of our study indicated that the seesaw balloon-wire cutting technique contributed to an encouraging procedural success rate and might be a useful complement to the methods described above. The new technique is quite different from the wire-cutting technique, which advances a balloon over the original guidewire to press the second guidewire that is withdrawn rapidly and intermittently. With the seesaw balloon-wire cutting technique, two balloons are advanced over two guidewires, respectively, and press both guidewires alternatively to crush the proximal cap of CTOs in multiple positions without pulling back any guidewires. One of the balloons provides extra support, facilitating the other balloon to pass through the CTO lesion. As a result, the seesaw balloon-wire cutting technique avoids the risk of injuring coronary artery ostium, and seems to be safer and more effective than the wire-cutting technique. Moreover, the seesaw balloon-wire cutting technique involves only conventional wires and balloons, so it has the advantages of easy operation, low cost, and decreased fluoroscopy time. Passing the second guidewire is a prerequisite for the seesaw balloon-wire cutting technique. In order to ensure the high success rate of this novel technique, some key points need to be highlighted. First, hydrophilic-coated and stiffer wires should be selected as the second guidewire due to the reduced resistance and good maneuverability. However, the operators have to avoid advancing the second guidewire into subintimal space to prevent the subsequent dissection. Second, microcatheters were used to improve the second guidewire maneuverability in most cases, which may be helpful in increasing the success rate of passing the second wire. Third, short and low-profile balloons are recommended and they should be inflated with high pressure (≥18 atm) to press the buddy guidewire to cut the proximal cap of CTOs in different positions. In terms of safety, no serious complications were observed in the present study.

Transradial PCI for CTOs has gained progressive acceptance in the last few years and growing evidence has demonstrated its benefits of earlier ambulation, shorter hospital stay, lower medical cost, fewer access-site complications, and patient preference.^11-14 In the present study, most CTO PCIs were performed by transradial approach. A disadvantage of the transradial approach is the weak backup support of guiding catheters. The seesaw balloon-wire cutting technique dramatically improves the backup support of guiding catheters and should be more suitable for transradial PCI of CTOs. However, there is an anatomy requirement for the technique. For ostial occluded lesions, the technique may be less effective. The reason is attributed to the mechanism of the technique. With this novel technique, the two balloons are progressed alternatively and one of the balloons provides extra backup for facilitating the other balloon to cross the CTO. Therefore, a certain distance from the occlusion to the ostium is needed. The major cause of failure in the seesaw balloon-wire cutting technique is the heavy circular calcification within the CTO lesion, which can be dealt with via use of a Rotablator. 

Study limitations. The present study enrolled only a small number of patients, and the seesaw balloon-wire cutting technique was not compared with other conventional methods, such as Tornus catheter and rotational atherectomy. Therefore, the efficacy and safety of this novel technique need to be further confirmed in future studies.

Conclusion

The present study shows that the novel seesaw balloon-wire cutting technique is a relatively simple, safe, and effective approach for facilitating balloon passage through resistant CTO lesions. 

References

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