Abstract: Background. Inability to cross the lesion with a balloon is the second-most common cause of technical failure, with the most common cause being the inability to cross with the wire. We propose a new, effective method for treating balloon-uncrossable lesions, called the “deep-wire crossing” (DWC) technique. Objectives. The aim of this study was to evaluate the procedural outcomes of the DWC technique for treating balloon-uncrossable lesions. Methods. From 2017 to 2018, a total of 95 patients with balloon-uncrossable lesions were treated using the DWC technique at our center. Procedural and in-hospital outcomes were assessed. Results. In most cases, the target vessel was the left circumflex (46.3%), followed by the right coronary artery (31.6%) and left anterior descending (22.1%). According to the American College of Cardiology/American Heart Association classification, 41% of lesions were classified as type C, 40% as type B2, and 18.9% as type B1. Chronic total occlusion occurred in 24 patients (25.3%). Overall technical success was achieved in 84 patients (88.4%). Successful DWC technique was achieved in 74 patients (77.9%). In-hospital major adverse cardiac event rate was 3.2%. Coronary perforation required pericardiocentesis in only 1 patient. Periprocedural myocardial infarction occurred in 1 patient and was managed conservatively; urgent revascularization was required for 1 patient. Conclusion. Our experience with the DWC technique demonstrated that it can be a viable option for treating balloon-uncrossable lesions, and operators should become familiar with it.
J INVASIVE CARDIOL 2019;31(12):E362-E368.
Key words: balloon-uncrossable lesion, chronic total occlusion, percutaneous coronary intervention
With the annual increase in the number of percutaneous coronary interventions (PCIs), the range of indications expands and procedures for complex coronary lesions become more frequent in many catheterization laboratories. Inability to cross the lesion with the wire is the most common cause of technical failure, while inability to cross with the balloon is the second-most common cause of technical failure.1,2 Such lesions require special surgical skills and additional devices, and are associated with a high risk of complications. Despite significant technical progress, the rate of procedural success in such lesions is low.3 A number of techniques have been proposed, and focus on either plaque modification (balloon-assisted microdissection technique, cutting balloons, atherectomy, laser, etc) or increasing guide-catheter support (guide-catheter extensions, anchor-balloon technique, deep guide-catheter intubation, buddy-wire technique, etc).4,5 However, these techniques all require additional equipment, which significantly increases the cost of the procedure.
We propose a new, effective method for treating balloon-uncrossable lesions called the “deep-wire crossing” (DWC) technique. In the DWC technique, a hydrophilic, polymer-jacketed guidewire crosses the lesion and advances into the ventricle/aorta through arterioluminal communications, thus providing a distal support for the entire system and helping to advance the balloon to a target segment.
The aim of this study was to evaluate procedural outcomes of the DWC technique for treating balloon-uncrossable lesions.
Patient population. We reviewed the baseline clinical and angiographic characteristics as well as the outcomes of 95 patients with balloon-uncrossable lesions that were treated using the DWC technique at our center between 2017 and 2018. The study was approved by our institutional review board.
Anatomical considerations of the DWC technique. The anatomical basis of this technique is the presence of communications between the coronary bed and the ventricular cavity, which were first described by Vieussens in 1706.6 He identified three forms of such connections. The first is vessels from 40-200 µm in diameter, directly connecting coronary arteries with the ventricle, later called arterioluminal vessels by J. Wearn.9 The second form provides connection through the vascular plexus, while the third form provides connection through coronary-venous communications, later described by Thebesius in 1708.8 Blood in the vessels of Vieussens can flow in both directions: toward the heart chamber and from the cavities into the myocardium. It has also been suggested that they are able to supply blood to the myocardium in the event of coronary artery occlusion, thus acting as a natural form of the nutrient channel.9 The existence of this type of communication was confirmed in a cadaver study by Estes et al.10 They first injected a special solution under high pressure (>100 mm Hg for 20 minutes) into the coronary arteries. Then, the heart was frozen and the sections were examined under the microscope. The authors discovered a large network of small arteries, up to 500 microns in diameter, extending from the epicardial arteries. They highlighted two classes of vessels: class A, comprising thin, numerous branches in the form of a network that penetrates three-quarters of the myocardial wall; and class B, which comprises vessels smaller in number, not prone to division, and reaching inner layers of the myocardium without decreasing the diameter of the lumen. Such vessels in the subendocardial layer form a vast network of anastomoses, which, according to several authors, plays an important role in protecting the subendocardial layer in the event of epicardial coronary damage.11,12 Some of these vessels have connections with the ventricular cavity (Figure 1).
The deep-wire crossing technique. To perform the DWC technique, the operator gently advances the hydrophilic, polymer-jacketed guidewire through the selected distal coronary artery branches, relying on the feel of the vessel under fluoroscopic control without contrast, similar to the surfing technique described by Sianos for retrograde recanalization of chronic total occlusions (CTOs) (Video 1).13
This technique can be used in the left anterior descending (LAD) artery, right coronary artery (RCA), and left circumflex (LCX) artery (Figure 2). When performing this technique, it is extremely important that the tip of the guidewire be oriented toward the heart chamber in order to avoid a perforation. Septal arteries from the LAD and RCA are anatomically directed to the ventricular cavity; thus, when using these arteries, the guidewire (repeating the path of the artery), is likely to fall into the ventricle. In the case of other arteries (marginal branches from the LCX, right posterolateral artery [PLA]), we usually use branches that arise perpendicularly from the main artery and are directed toward the ventricular cavity. The main movement of the guidewire is a rapid rotation. If the wire bunches up, then it is meeting the resistance and is not in the correct channel. In this case, the operator must carefully pull the wire back and redirect it to another channel. If the tip of the wire begins to move quickly, single ventricular extrasystoles appear on the electrocardiogram, and then the wire is within the ventricular cavity. It is worth noting that the guidewire can enter both the right and left ventricle through arterioluminal connections. Mostly, we do not focus on this because our goal is to achieve a high support for the entire system by advancing the guidewire more distally, to the ventricular cavity and great artery. When performing this technique, it is extremely important to enter the ventricle. The stages of the DWC technique are shown in Figure 3.
As mentioned before, we use guidewires with a soft polymeric tip and hydrophilic coating, which allows the wire to pass through arterioluminal vessels into the cavity of the ventricle with minimal pushing movements, following the path of least resistance. According to our experience, the shape of the guidewire’s tip is not a determining factor, since in most cases the operator cannot predict a balloon-uncrossable situation. Undoubtedly, the less the tip is curved, the easier it will be to pass the guidewire through small vessels into the ventricular cavity. Suitable guidewires for the DWC technique are polymer jacket wires, such as Fielder FC, XT, and Sion Black (all Asahi Intecc), as well as Pilot 50 and Whisper (both Abbott Vascular).
Definitions. Balloon-uncrossable lesion was defined as a lesion that could not be crossed with a small-sized (1.2-1.5 mm) balloon after successful guidewire advancement with optimal guide-catheter position and that required additional treatment steps, such as anchoring techniques, guide-catheter extensions, Tornus, rotational atherectomy, etc. Technical success was defined as successful stent deployment(s) with achievement of <30% residual stenosis and TIMI 3 flow. Procedural success was defined as the achievement of technical success with no in-hospital major adverse cardiac event (MACE). In-hospital MACE included any of the following adverse events prior to hospital discharge: death from any cause, myocardial infarction (MI), recurrent angina requiring urgent repeat target-vessel revascularization with PCI or coronary artery bypass surgery (CABG), or tamponade requiring pericardiocentesis or surgery. Successful DWC technique was defined as successful wire advancement into the ventricular cavity. Coronary artery lesions were classified according to American College of Cardiology/American Heart Association (ACC/AHA) into types A, B, and C.14
CTO was defined as coronary lesions with TIMI flow grade 0 for at least 3 months.15 MI was defined using the Fourth Universal Definition of Myocardial Infarction.16 Urgent revascularization was defined as emergency CABG or repeat PCI within 24 hours at the same target vessel. Calcification was assessed by angiography as mild (spots), moderate (involving 50% of the reference lesion diameter), or severe (involving >50% of the reference lesion diameter). Moderate proximal vessel tortuosity was defined as the presence of at least 2 bends >70° or 1 bend >90° and severe tortuosity as 2 bends >90° or 1 bend >120°. Ostial lesion was defined as a significant stenotic lesion located within 5 mm of the ostium.17
Clinical and angiographic characteristics. A total of 95 patients were enrolled in the study; baseline clinical and demographic characteristics are shown in Table 1. The average age was 57.9 ± 9.1 years, and 77.9% were men. Of these patients, 45.3% had class III-IV angina according to the Canadian Cardiovascular Society (CCS). All patients had hypertension, 43.0% had dyslipidemia, 21.0% had diabetes mellitus, and 12.0% had chronic kidney disease. Seventy-one patients (75.0%) had a history of previous MI. Previous PCI and CABG occurred in 56 patients (58.0%) and 42 patients (44.0%), respectively.
Angiographic data are presented in Table 2. The target vessel was the LCX in most cases (46.3%), followed by the RCA (31.6%) and LAD (22.1%). According to the ACC/AHA classification, 41.0% of the lesions were type C, 40.0% were type B2, and 18.9% were type B1. Calcification was present in 83 cases (87.3%), including moderate and severe in 25 cases (26.3%) and 20 cases (21.0%), respectively. Moderate to severe tortuosity was present in 49 cases (51.6%). Fourteen patients (14.7%) had ostial lesions. CTO occurred in 24 cases (25.3%). Mean J-CTO score was 1.9 ± 0.9 and mean Syntax score was 24.8 ± 10.6.
Procedure outcomes. Technical characteristics are shown in Table 3. Overall technical success was achieved in 84 cases (88.4%). The radial artery was the predominant access site (67.4%) and 6 Fr guiding catheters were used in the majority of cases (70.5%). High-support guide catheters for the right (JR, AL, EBU) and left coronary arteries (CLS, AL, XB, ML) were chosen. In all cases, attempts to pass a low-profile (1.25-1.5 mm) balloon were unsuccessful. Successful DWC technique was achieved in 74 cases (77.9%), which allowed successful stent deployment in 62 cases (65.3%), whereas additional techniques were necessary in 9 cases (guide-extension catheter in 4 cases, Tornus catheter [Asahi Intecc] in 3 cases, and anchoring technique in 2 cases). In 13 cases with unsuccessful DWC technique, the procedures were finished with stent implantation using other techniques, such as rotational atherectomy in 6 cases, anchoring technique in 3 cases, guide-extension catheter in 2 cases, and deep guide-catheter intubation in 2 cases (Figure 4). Mean fluoroscopy time was 28 ± 15 minutes and mean contrast volume was 140 ± 50 mL.
In-hospital outcomes. In-hospital MACE rate was 3.2%. Device-related complication (perforation) occurred in 3 cases (3.2%), with only 1 case (1.1%) requiring pericardiocentesis. Two other cases were complicated by type IV perforation into the anatomical cavity (heart chamber), which did not require additional intervention. Periprocedural MI occurred in 1 case due to side-branch occlusion and was managed conservatively; 1 patient with unstable angina required urgent CABG due to technical failure (Table 4).
Clinical case. A 68-year-old man presented to our hospital with stable angina (CCS class III); he had CABG 2 years ago for multivessel coronary artery disease. In addition, he underwent LCX-PCI 1 month ago. Electrocardiogram showed a normal sinus rhythm and echocardiogram revealed normal systolic function. Diagnostic coronary angiography demonstrated proximal LAD-CTO, RCA-CTO with Rentrop grade 3 collaterals from the LAD to the distal RCA, totally occluded saphenous vein grafts to obtuse marginal artery and RCA, and patent left internal mammary artery to LAD, as well as LCX stent with no restenosis.
PCI of the RCA-CTO started with bilateral transradial approach after guide catheter insertion using 6 Fr JR4 to the RCA ostium and 6 Fr JL 3.5 to the LCA ostium. The proximal stump was penetrated with a Gaia 2 wire (Asahi Intecc), and a Pilot 200 wire was then passed to the acute marginal (AM) branch using a parallel-wire technique. After several failed attempts to redirect the second guidewire to the distal RCA, it was decided to dilate the CTO segment above the AM.
Due to calcification, multiple attempts to deliver a 1.5 x 15 mm semicompliant balloon failed; the Whisper MS wire was advanced parallel with the Pilot 200 to the AM and further into the left ventricle and ascending aorta using the DWC technique. After predilation with a 1.5 x 15 mm semi-compliant balloon, the Pilot 200 wire was redirected to the distal RCA. Next, the distal CTO segment was passed using a Progress 120 wire (Abbott Vascular). After predilation of the occluded segment, a critical stenosis of the right PLA was revealed. Since the balloon could not be delivered, DWC technique was performed again, allowing successful balloon advancement. Balloon angioplasty of the PLA lesion was then performed and 3 drug-eluting stents were deployed to fully cover the RCA-CTO segment (Figure 5).
As far as we know, our study represents the first experience using the DWC technique. The success rate of this technique was 78%. In only 1 case (1.1%), perforation occurred requiring additional treatment (pericardiocentesis). This case occurred early in the learning curve; the operator did not finish the technique and did not make sure the guidewire was in the ventricle. Leaving the guidewire in the intramural vessels, he continued the intervention and further manipulations eventually led to perforation (Figure 6; Video 2). In 2 other cases, perforations were classified as type IV (Figure 7) and were managed conservatively due to favorable prognosis, as shown in other studies.18,19 Thus, technique-related complications (perforations) occurred in 3 cases (3.2%), which is comparable with other techniques used for this lesion type.20-22 In order to minimize the risk of complications, we always try to use septal arteries. Thus, septal arteries were used in 40 cases (42.0%) in the current study. It is noteworthy that the rate of successful DWC was approximately the same regardless of the target artery (75%, 80%, and 80% for LCX, LAD, and RCA, respectively). Thus, this technique is suitable for any coronary artery (Video 3).
The use of radial access for PCI has been steadily growing worldwide.23 Benefits influencing this major change in practice over the past decade include fewer bleeding complications, lower morbidity, earlier ambulation, lower total hospital costs compared with transfemoral approach, patient preference and comfort, easy to compress and achieve hemostasis, and less chance of developing ischemia due to dual blood supply of the hand.24-26 Nowadays, radial access has been extended to more complex cases, demonstrating both safety and effectiveness.27 Besides, radial access can be suitable for most techniques used in balloon-uncrossable lesions. In our study, the transradial approach and 6 Fr guide catheters were used in the majority of cases (67.4%), with an overall technical success rate of 88.4%. Conversion from radial to femoral access occurred in 1 case.
The mechanism of crossing small vessels and entering into the ventricular cavity remains unclear. To date, there are two hypotheses. The first is that the passage of the guidewire into the ventricle is carried out through microvessels by finding a microchannel connecting to the cavity (arterioluminal vessels). The second is that the wire causes clinically insignificant perforation of the intramural vessels and reaches the cavity, sometimes causing type IV perforation.
A definitive advantage of the DWC technique is that it provides good support without an increase in the duration or cost of the procedure. Another advantage of this technique is that it allows the operator to continue working with the same guidewire without changing the guide catheter or using an additional guidewire. Moreover, it does not exclude the use of other techniques, and thus is an additional tool for balloon-uncrossable lesions. The main limitation of this technique is the possibility of coronary artery perforation with the wire. To prevent this complication, proper guidewire selection and careful wire manipulation are extremely important. For example, in cases of CTO recanalization performed with stiff wires, the implementation of this technique can lead to perforation of the coronary arteries. In our clinical case demonstrating the DWC technique during CTO-PCI, we advanced a Whisper MS wire parallel to a Pilot 200 wire in order to minimize the risk of perforation. Also, it is not always possible to advance a guidewire into a ventricle, yet our study shows a high success rate with this technique (78.0%). In this context, it is important to emphasize that the DWC technique is highly dependent on operator experience, and the learning process may be time consuming.
Study limitations. Potential limitations of this study should be considered. First, this study was limited by its retrospective, observational design. Second, results of this study could be influenced by selection criteria and operator experience. Third, the definition of “balloon-uncrossable lesion” is subjective and depends on operator experience. It is noteworthy that all procedures were performed by experienced operators with >300 PCIs per year. Finally, our results cannot be directly compared with other techniques used in such lesions because of different anatomic settings.
Our experience with the DWC technique demonstrated that it can be a viable option for treating balloon-uncrossable lesions, and thus operators should become familiar with it.
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From the Division of Invasive Cardiology, Meshalkin National Medical Research Center, Ministry of Health of Russian Federation, Novosibirsk, Russian Federation.
Disclosure: The authors have completed and returned the ICMJE Form for Disclosure of Potential Conflicts of Interest. The authors report no conflicts of interest regarding the content herein.
The authors report that patient consent was provided for publication of the images used herein.
Manuscript submitted February 13, 2019, provisional acceptance given February 25, 2019, final version accepted May 31, 2019.
Address for correspondence: Dmitrii Khelimskii, MD, Meshalkin National Medical Research Center, Ministry of Health of Russian Federation, Division of Invasive Cardiology, 15 Rechkunovskaya Street, Novosibirsk, Russia 630055. Email: email@example.com