Novel Use of the Heartrail Catheter as a Thrombectomy Device

ABSTRACT: The presence of thrombus is independently associated with adverse outcomes during percutaneous coronary intervention (PCI), particularly in those cases involving a large thrombus burden such as in saphenous vein grafts (SVGs) or during primary PCI. Mechanical thrombectomy devices are used to reduce the thrombus burden in such high-risk procedures to reduce the risk of distal embolization and slow flow and no-reflow. Here we describe 3 cases of successful use of a stent delivery system with a wide-bore lumen, the “five-in-six” Heartrail catheter, as a thrombectomy device in SVG lesions and primary PCI following failure of conventional simple aspiration thrombectomy catheters. J INVASIVE CARDIOL 2011;23:35–40 Key words: thrombectomy; five-in-six Heartrail catheters ———————————————————— The presence of thrombus is independently associated with adverse outcomes during percutaneous coronary intervention (PCI) and is thought to be due to dislodgement of thrombotic material, causing distal embolization and leading to slow flow or even no-reflow. The National Heart, Lung, and Blood Institute (NHLBI) Dynamic Registry has shown an almost two-fold increase in in-hospital major adverse cardiovascular events (MACE) rates observed in PCI procedures in which there is visible thrombus.¹ Such risks are even greater in the setting of acute myocardial infarction and primary PCI, in which distal embolization rates may be as high as 15% and are associated with a significantly increased 5-year mortality rate of 44% compared to 9% in those patients without distal embolization.² Prevention of no-reflow is a major objective during primary PCI, as this condition has repeatedly been associated with a worse prognosis on follow up.³ Mechanical thrombectomy devices and distal protection devices are widely used in clinical practice and have been introduced to reduce the burden of thrombus and the incidence of distal embolization in high-risk procedures with large thrombus burden such as during primary PCI or saphenous vein graft (SVG) interventions.⁴ However, optimal thrombectomy is not always achieved, particularly in cases involving a large thrombus burden. We have previously described the use of the Terumo 5 French (Fr) Heartrail II catheter (Terumo, Japan) within a standard 6 Fr guiding catheter (so-called “five-in-six” system) to achieve extra-deep coronary intubation and aid stent delivery in both native coronary vessels and coronary artery bypass grafts.^5,6 Here, we describe the use of the Terumo “five-in-six” Heartrail catheter as a thrombectomy device following failure of conventional 6 Fr simple aspiration devices during SVG PCI and in native coronary vessels during primary PCI.

Heartrail Thrombectomy Catheter Technique

We have previously described our technique for introduction of the Heartrail catheter into native coronary vessels and SVGs.^5,6 Briefly, the Heartrail “five-in-six” system involves insertion of an extra-length 5 Fr soft-tipped catheter into a standard 6 Fr guide catheter so that the distal tip of the 5 Fr catheter can extend or “telescope” up to 16 cm beyond the tip of the 6 Fr catheter. The hemostatic valve is disconnected from the guide catheter once the guide catheter and coronary wire are in position. The Heartrail device is passed through the guide catheter into the target vessel over a coronary wire to deliver the catheter to the site of thrombus. The hemostatic valve is then re-attached to the end of the Heartrail catheter, and aspiration of thrombotic material is performed through the Y-piece of the hemostatic valve using a 20 ml luer-lock syringe. Once thrombus aspiration is finished, the hemostatic valve is disconnected from the Heartrail catheter, and the Heartrail can be removed. Finally, the hemostatic valve can be re-connected to the guide catheter after flushing it with saline to reduce the risk of any thrombus remaining within the valve.

Case 1

A 73-year-old Caucasian male with a previous history of coronary artery bypass grafting (CABG) in 1998 and subsequent PCI to his native left circumflex artery (LCX), right coronary artery (RCA) and his SVG supplying the first diagonal (D1) in 2007, was admitted with an acute coronary syndrome (ACS) in September 2009. His electrocardiogram (ECG) showed dynamic anterior ST depression and echocardiography confirmed good left ventricular (LV) systolic function. Cardiac catheterization demonstrated that the previously stented SVG-to-D1 was occluded (Figure 1). It was clear that the latter was the cause of the index event, thus a decision was made to perform PCI to the SVG of the D1 vessel. The procedure was covered with weight-adjusted intravenous (IV) heparin, but no glycoprotein (GP) IIb/IIIa inhibitor was used. An LCB guide catheter (Cordis Corp., Miami Lakes, Florida) was used to intubate the vessel, although it proved difficult to advance the 0.014 inch, 182 cm ChoICE PT extra-support guidewire (Boston Scientific Corp., Natick, Massachusetts) through the vessel. Therefore, a 1.8 mm x 130 cm Finecross MG catheter (Terumo) was used to achieve optimal wire position. Initial attempts at thrombus aspiration using a 6 Fr Export thrombectomy catheter (Medtronic, Inc., Minneapolis, Minnesota) were unsuccessful, as we were unable to deliver the catheter to the site of thrombus due to significant resistance in the previously stented segment. We therefore predilated the previously stented segment with a 2 x 15 mm Ryujin compliant balloon (Terumo) before initial thrombectomy with an Export catheter (Medtronic) as well as with a 4 Fr Pronto low-profile extraction catheter (Vascular Solutions, Inc., Minneapolis, Minnesota). However, despite attempts at thrombectomy using both catheters, there was little resolution of the heavy thrombus burden that was visualized (Figure 2). Therefore, a Heartrail “five-in-six” catheter was used as a thrombectomy catheter due to its larger internal luminal diameter (0.059 inch) compared to either the Export thrombectomy catheter (0.040 inch) or the Pronto LP catheter (0.056 inch) with good success, with a significant reduction in thrombus burden visualized and a significant improvement in vessel flow (Figures 3 and 4). Furthermore, large volumes of well-organized thrombus were retrieved following thrombectomy with the Heartrail catheter (Figure 5). The diseased segment was then stented with a 2.75 x 38 mm Xience everolimus-eluting stent (Abbott Vascular, Santa Clara, California) overlapped with another Xience stent (2.75 x 33 mm) proximally to cover the ostium, rendering a satisfactory final result (Figure 6). Following the procedure, the patient made an uneventful recovery and his post-procedural troponin T (TnT) and creatine-kinase (CK) were 0.02 ng/ml and 24 µ/L, respectively. He remains well at follow up.

Case 2

A 58-year-old Afro-Caribbean male with a strong family history of premature coronary artery disease (CAD) was transferred to our center for primary PCI following an anterior ST-segment elevation myocardial infarction (STEMI). En route to the catheterization laboratory, he developed ventricular fibrillation (VF) and was successfully cardioverted following direct current cardioversion (DCC). Diagnostic cardiac catheterization revealed a large filling defect within the mid left anterior descending artery (LAD), representing a large thrombus situated just after a septal vessel, though the distal vessel remained patent (Figure 7). Under weight-adjusted IV heparin and abciximab cover (Repro, Eli Lilly & Company, Indianapolis, Indiana), primary PCI was performed and an XB 3.5 guide catheter (Cordis, Miami Lakes, Florida) was used to enter the left coronary artery. The lesion was easily crossed with a 0.014 inch, 182 cm Choice PT extra-support guidewire (Boston Scientific Corp. Natick, Massachusetts) and attempts were made to extract the thrombus using a 6 Fr Export thrombectomy catheter, although there appeared to be little resolution of the large filling defect (Figure 8). At this point we elected to use the Heartrail “five-in-six” catheter as a thrombectomy device with significant thrombus aspiration achieved and a significant reduction in thrombus load visualized angiographically (Figures 9 and 10). We directly stented the lesion with a Presillion 4 x 24 mm bare-metal stent (BMS) (Cordis), followed by postdilatation with a Quantum Maverick 4.5 x 12 mm compliant balloon (Boston Scientific) at high pressure, yielding an excellent angiographic result (Figure 11). The patient’s TnT 12 hours post procedure was 1.14 ng/ml. He underwent an uneventful recovery and was discharged home 4 days later and remains stable at 4-month follow up.

Case 3

A 58-year-old hypertensive Asian male presented to our tertiary center with an anterior STEMI. He was transferred for primary PCI where he received 300 mg of aspirin and 600 mg of clopidogrel. Coronary angiography revealed an occluded mid-LAD artery immediately after the first septal branch with initial thrombolysis in myocardial infarction (TIMI) flow 0 (Figure 12). The procedure was covered with weight-adjusted IV heparin and a GP IIb/IIIa inhibitor. A 6 Fr EBU 3.5 guide catheter (Cordis) was used to engage the left coronary artery and the lesion was easily crossed with a BMW guidewire (Abbott Vascular, California). Although the initial angiographic images did not suggest the presence of a significant thrombus burden, we elected to perform thrombectomy using the 6 Fr Export thrombectomy catheter. We then predilated the lesion using a 2 x 12 mm Maverick balloon and stented the diseased vessel with a 3 x 28 mm Cypher sirolimus-eluting stent (Cordis) (Figure 13). Immediately following the deployment of the stent, we noticed the development of acute stent thrombosis with a large amount of thrombus within the stent (Figures 14 and 15) and further ST elevation in the anterior chest leads. A 6 Fr Export thrombectomy catheter was initially used to attempt thrombus aspiration, however, no significant thrombus was aspirated and the vessel remained occluded with TIMI 0 flow (Figure 16). We elected to use a Heartrail “five-in-six” catheter as a thrombectomy device (Figure 17), with good thrombus aspiration success from within the stent (Figure 18). The patient’s 12-hour TnT was 5.66 ng/ml and his C-K was 1,613 u/L. He was discharged with no further complications observed while an inpatient.

Discussion

To the best of our knowledge, for the first time in the literature we report the successful use of the Heartrail catheter as a thrombectomy device in 3 cases in which conventional 6 Fr thrombectomy devices had failed to achieve optimal thrombus aspiration. The first case was a saphenous vein graft with a large thrombus burden following presentation with an ACS, whilst the remaining 2 cases were primary PCI cases in which either a large thrombus burden was present initially (Case 2) or post stent deployment in the setting of an acute stent thrombosis (Case 3). There were no complications observed in any of these cases with the use of the Heartrail catheter such as trauma to the vessel or visible embolization of either air or thrombus. The Heartrail II catheter is a 120 cm soft-tipped 5 Fr catheter that fits within a standard 6 Fr catheter and can extend up to 16 cm distal to the tip of the guide catheter (“five-in-six” system). We have previously reported the use of the Heartrail catheter as a distal stent delivery device^5,6 by means of extra-deep intubation of native and graft vessels as well as a means to achieve deep selective intubation and opacification of native coronary vessels in both the acute and elective setting in order to minimize contrast use in patients with severe renal dysfunction, thereby reducing the potential for contrast-induced nephropathy.⁷ Over the past 3 years, our center has performed close to 200 procedures using the Heartrail catheter in native coronary vessels, SVGs and left interior mammary artery (LIMA) grafts, and we have not experienced vessel dissection, stent disruption or embolization of thrombus or atheromatous material into the distal vessel. Thrombectomy devices are widely used in primary PCI to reduce the incidence of distal embolization and slow flow and no-reflow which are associated with larger infarct size, more significant LV dysfunction, a greater risk of cardiac death and non-fatal cardiac events.^3,4 One of the main factors associated with an increased incidence of distal embolization and no-reflow is the presence of a large thrombus burden that can limit reperfusion at the microvascular level. Indeed, a large thrombus burden is associated with nearly two-fold greater MACE rates and is a strong independent predictor of longer-term mortality.⁸ A recent patient-pooled analysis of 11 trials involving 2,686 patients has demonstrated that thrombectomy use in STEMI was associated with a decrease in total mortality and MACE rates, although the clinical benefit was confined to patients treated with simple mechanical thrombectomy devices.⁹ The risk of distal embolization and slow-flow/no-reflow are not only limited to primary PCI cases, but has a high incidence in PCI procedures involving SVGs, which often have a high burden of thrombotic material. The presence of thrombus in SVG PCI is independently associated with a four-fold increase in 30-day MACE rates,¹⁰ and visible distal embolization may occur in 15–20% of procedures.¹¹ Although the use of distal embolic protection devices has been shown to improve clinical outcomes in SVG PCI, the benefit of thrombectomy in such cases is less clear.⁴ It is not always possible to achieve optimal thrombectomy, particularly in cases involving a large thrombus burden, since many of the current simple thrombectomy devices have a relatively small lumen and Poiseuille’s law states that the laminar flow rate of an incompressible fluid along a vessel is proportional to the fourth power of the vessel’s radius. Hence, flow rates achievable to extract thrombus using such simple thrombectomy catheters may be limited by the radius of the catheter lumen. Furthermore, in contrast to thrombus burden related to STEMI, where thrombus is mainly fresh and may be relatively easier to extract, the thrombus burden in SVG cases is one of complex, bulky atheromatous, well-organized and highly viscous, which would further lead to difficulties in extraction. In our 3 cases, in which simple thrombectomy devices failed to achieve adequate thrombectomy, necessitating the use of the Heartrail “five-in-six” catheter (internal luminal diameter 0.059 inch), an export catheter (internal luminal diameter 0.040 inch) was initially used in 3 of the cases and a Pronto LP catheter (internal luminal diameter 0.056 inch) was initially used in 1 case. Through Poiseuille’s law, flow achieved through a Heartrail catheter would be 3.2-fold greater than an Export catheter and 1.2-fold greater than a Pronto LP catheter, which may in part explain the more optimal thrombectomy results achieved in cases following use of the Heartrail catheter. The use of wider-bore thrombectomy devices has been compared previously in primary PCI cases in which patients were prospectively treated with a Diver large internal lumen catheter (Invatec, Roncadelle, Italy) and outcomes were compared with a matched population of the TAPAS trial (Thrombus Aspiration during Percutaneous coronary intervention in Acute myocardial infarction Study)¹² in which patients were treated with a smaller-sized Export catheter.¹³ The larger internal lumen diameter of the Diver catheter did not result in retrieval of larger thrombotic particles, nor in improved angiographic or electrocardiographic outcomes in this study. It is likely that the routine use of larger thrombectomy catheters does not achieve better outcomes than standard-sized thrombectomy catheters, however, in cases such as those presented here, in which the thrombus burden was significant, thrombectomy catheters that have a larger internal lumen may have an additional benefit. Use of the Heartrail catheter in these situations would have the advantage in that many thrombectomy devices used in cases of large thrombus burden, or following suboptimal results with simple thrombectomy devices, such as the X-sizer or ThromCat (Kensey Nash Corp., Exton, Pennsylvania) devices, or hydrodynamic thrombectomy systems such as the AngioJet (Medrad, Inc., Warrendale, Pennsylvania) are more complex to use and have had mixed outcomes in larger studies.⁴ Indeed, in a recent pooled analysis involving 11 trials of 2,686 patients, subgroup analysis of 871 patients enrolled in trials involving the use of complex devices such as the X-Sizer (EndiCor Medical, Inc., San Clemente, California), Angiojet (Medrad), Rescue (Boston Scientific), and TVAC devices (Nipro, Osaka, Japan), did not improve mortality outcomes compared to standard PCI in the setting of primary PCI.⁹ Several of the simple mechanical devices are also available as 7 Fr systems for use in cases involving a larger thrombus burden, however, the advantage of the Heartrail system is that it is 6 Fr-compatible and obviates the need to upsize to a 7 Fr system during the procedure with the potential risk of losing guidewire position.

Potential Limitations of the Technique

Use of the bulkier Heartrail catheter in SVG cases where thrombectomy is required increases the potential risk for embolization during passage of the device before an embolic protection device can be placed distal to the occlusion. However, in such cases with a large thrombus load, passage of the distal protection device itself may cause distal embolization prior to deployment. Furthermore, extra care should be taken during the introduction or removal of the Heartrail catheter to avoid risks of air embolization, although in our experience of over 200 cases involving the Heartrail catheter, this has not been found to be a major problem when necessary care is taken.

Conclusion

The Heartrail “five-in-six” catheter is a safe, alternative new thrombectomy device technique during PCI cases where there is a large thrombus load after failure of conventional aspiration devices. We would currently only advocate its use after conventional means have failed and not as a first-line system.

References

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From the *Cardiology Department, University Hospital of Northern British Columbia, Prince George, B.C., Canada; and †Manchester Royal Infirmary, Central Manchester University Hospitals NHS Foundation Trust, Manchester, United Kingdom. The authors report no conflicts of interest regarding the content herein. Manuscript submitted June 2, 2010, provisional acceptance given July 7, 2010, final version accepted September 7, 2010. Address for correspondence: Dr. M. A. Mamas, Manchester Heart Centre, Manchester Royal Infirmary, Oxford Road, Manchester, United Kingdom M13 9WL. E-mail: mamasmamas1@yahoo.com