Crossing a Chronic Total Occlusion Using Combination Therapy with Tornus and FlowCardia

More than 25 years after the introduction of angioplasty, percutaneous recanalization of coronary artery chronic total occlusions (CTOs) remains a technical challenge with a lower success rate than most other lesions attempted.¹ The presence of a CTO is the most frequent reason for excluding percutaneous coronary intervention (PCI) as an option for revascularization. The fibrous cap at the proximal and distal ends of the CTO may make passage through the CTO extremely difficult.² Success rates in multiple series range from 54–63%, with more current success rates being reported at more than 70%. Newer technological advances, which include stiffer, tapered-tipped, and hydrophilic wires, as well as optical coherence reflectometry with radiofrequency ablative energy, have in part been responsible for this increased success.³ CTOs are most commonly defined as a coronary vessel with at least one stenotic lesion demonstrating TIMI 0–1 flow which has been present for at least six weeks. Acute myocardial infarction and occluded saphenous vein grafts have been excluded from the definition. Procedural success has been defined as crossing the CTO with a wire and balloon, resulting in less than 40% residual stenosis and no in-hospital major adverse cardiac events (MACE). We present the first case report of a patient treated with the Tornus Specialty Catheter (Abbott Vascular^® Devices, Redwood City, California). Case Presentation A 53-year-old male with a history of coronary artery disease, hypertension, dyslipidemia and gout presented with exertional angina refractory to traditional medical therapy. Coronary arteriography demonstrated a widely patent proximal left anterior descending artery stent and CTO of the mid-right coronary artery with left-to-right collaterals. There was no angiographic evidence of coronary artery disease in the circumflex artery. Previous noninvasive studies demonstrated ischemia in the inferior distribution. Bilateral femoral arterial access was obtained for dual injection arteriograms with a 7 Fr sheath in the right femoral artery and a 4 Fr sheath in the left. A 7 Fr JR4 guiding catheter and 4 Fr JL4 diagnostic catheter was used for simultaneous injections. After unsuccessfully crossing the CTO with a 2.3 Fr Rapid Transit and Miracle Bros 3 wire (Abbott Vascular), the wire and transit catheter were removed and exchanged for the FlowCardia Crosser catheter (FlowCardia, Sunnyvale, California) and 0.014 inch Miracle Bros 3 wire. Multiple bursts of vibrational energy were delivered with successful passage beyond the proximal CTO cap. The wire, which had not worked previously with traditional methods, then passed through three-quarters the length of the CTO. However, the wire was unable to pass beyond the distal cap, even with FlowCardia energy, therefore the FlowCardia device was removed and exchanged for the 2.1 Fr Tornus catheter (Abbott Vascular). With counter-clockwise rotation of the catheter, the wire passed partially though the distal cap. This wire was removed and exchanged for a .014 inch Whisper wire (Guidant Corp., Indianapolis, Indiana), which in turn was replaced with the 0.014 inch Asahi Prowater wire (Abbott Vascular). Further manipulation of the Tornus yielded successful passage beyond the distal cap of the CTO. With the wire maintained in position, the Tornus catheter was removed and traditional angioplasty using a 2.5 x 20 mm Maverick balloon (Boston Scientific Corp., Natick, Massachusetts) was performed, and two 3.5 x 32 mm Taxus^® stents (Boston Scientific) were placed at the level of the CTO. A 2.5 x 12 mm Taxus stent was placed distal to the CTO in the right coronary artery. Post-stent angiography demonstrated TIMI 3 flow, with no dissection or perforation. Discussion CTOs are common in patients with coronary artery disease. A registry by Christofferson et al demonstrated that 30–50% of all patients presenting with critical coronary artery disease (single vessel of at least 70%) have at least one chronic total occlusion.⁴ Novel technologies have been used to treat CTOs with various published success rates. Successful revascularization of CTOs leads to improved survival and decreased major adverse events.⁵ In a study by Suero et al, 75% of the patients studied had multivessel disease. If a patient had single-vessel disease, technical success was more likely (27% vs. 18%,), whereas if a patient had three-vessel disease, technical failure was more likely, and finally, if a patient had two-vessel disease, the likelihood of success or failure was the same. MACE was also matched at 3.8%, regardless of whether the procedure was a success or failure. Patients who had a successful revascularization of the occluded segment had a significantly higher survival rate at 10 years compared to the failure group (73.5% vs. 65%). A successfully revascularized CTO confers a significant 10-year survival advantage compared with failed revascularization.⁶ At 12 months, patients with a successful procedure experienced a lower incidence of cardiac death or myocardial infarction (1.05% vs. 7.23%), a reduced need for coronary artery bypass surgery (2.45% vs. 15.7%), and were more frequently free of angina (88.7% vs. 75.0%) compared with patients who underwent an unsuccessful procedure.⁷ Although left ventricular function has not been shown to improve with recanalization of a CTO, a series by Baks et al demonstrated improvement of more than 10% in absolute systolic wall thickness in 76% of dysfunctional segments. Early experience with the FlowCardia Crosser catheter showed it to be effective in opening the proximal cap of the total occlusion. However, in a few cases, it was not sufficient in crossing the distal cap, and the channel created was not large enough to allow passage of a balloon catheter. The Tornus catheter was designed as a support catheter that can be used in this specific circumstance and in similar situations where support is imperative. One should note that it is not necessary to cross the fibrous cap with the FlowCardia in every case before using the Tornus catheter. In fact, the Tornus may be used as the primary approach. The Tornus catheter consists of several steel strands that are braided to enhance strength and flexibility. It also contains a safety release valve at the proximal end of the catheter to ensure the catheter is not over-rotated. The Tornus tip is easily visualized thanks to its opaque marker. The device is available in 2.1 Fr and 2.6 Fr sizes (Figure 5). Using counter-clockwise rotation of the catheter, the threaded taper tip seems to embed and advance into the CTO, delivering enough support to pass through the remaining CTO. Also, the Tornus is an over-the-wire system allowing for wire exchange if a more supportive wire is required. These features not only contribute to the increased likelihood of successful balloon angioplasty, but improve the likelihood of stenting.⁸ Patency rates have been found to be higher with stent implantation when compared to balloon PTCA in the setting of CTO revascularization.⁹ More specifically, drug-eluting stents significantly reduce the incidence of restenosis and reocclusion when compared to bare-metal stents or plain-old balloon angioplasty.¹⁰ The Tornus catheter may be used alone or in combination with other devices such as the FlowCardia. The lack of “bells and whistles” and the seemingly intuitive design makes this catheter extremely appealing.

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