When Angle Gets too Wide
Dr. David LO
Yan Chai Hospital, Hong Kong
An 86-year-old gentleman was admitted to hospital due to acute onset chest pain. He was an ex-smoker with background medical history of hypertension, hyperlipidaemia and diabetes mellitus. He was independent in terms of his activity of daily living. His ECG showed ST depression in anterior leads and blood test showed elevated level of cardiac troponin. The diagnosis was high risk NSTEMI. Coronary angiogram showed there was mild diffuse disease in RCA (Movie 1, Movie 2), and a critical stenosis at the distal left main vessel followed by 80% stenosis at the proximal LAD artery (Movie 3, Movie 4, Movie 5). From the LAO cranial view (Movie 6), there was haziness at the LCx artery ostium raising the suspicion of significant ostial disease. Therefore, wiring of the LCx artery was warranted.
The learning point in this case was that wiring of LCx artery (side branch) was extremely difficult due to the wide bifurcation angle (retroflex LCx artery) and large plaque burden at the site of bifurcation (Movie 7 – AP caudal view, Movie 8 – 45 Cranial 15 RAO view, Figure 1). The distal LAD artery was wired by workhorse guidewire easily. However, attempt in wiring of LCx artery by workhorse guidewire or hydrophilic wire with polymer coating were failed, even after shaping the tip of the guidewires with a wide bend. Pullback wiring technique and wiring supported by microcatheter and double-lumen microcatheter were failed as well.
The reverse wire technique, firstly described by Kawasaki et al. in 2008, can be considered in wiring markedly angulated side branch. However, the significant stenosis proximal to the bifurcation in our patient hampered the delivery of the reverse guidewire system, making this case not suitable for such technique.
SuperCross Microcatheter (1200 angled tip) was used in our patient. The LCx artery was wired successfully with Fielder FC supported by this angled tip microcatheter (Figure 2, Figure 3, Movie 9, Movie 10, Movie 11).
After successful wiring, IVUS confirmed there was severe disease at ostial LCx and the left main bifurcation lesion was treated by DK Crush stenting technique under IVUS guidance. Ostial LCx was stented with 2.75/18mm stent and proximal LAD to left main was stented with 3.5/34mm stent. Kissing balloon inflation was done with 3.5mm NC balloon at ostial LAD and 2.75mm NC balloon at ostial LCx. Left main was post-dilated with 4.5NC balloon. Final IVUS and angiographic results were good (Movie 12, Movie 13, Movie 14, Movie 15).
Comment
The complex pattern of bifurcation coronary anatomies and the different pattern of atherosclerotic disease distribution may render targeted vessel wiring highly challenging. There are several techniques, which have been proposed to overcome the difficulty of guidewire crossing in angulated lesions. Pullback wiring technique, reverse guide wire technique and the use microcatheter / double-lumen microcatheter can be considered. Main vessel balloon pre-dilation is a “last resort” strategy to wire the side branch. Indeed, this technique is basically not advisable in the vast majority of bifurcated lesions as it may result in side branch occlusion. Finally, when the side branch access is prevented by excessive atherosclerotic disease in the main vessel, the use of debulking techniques (like rotational atherectomy) can be considered. In our patient, side branch wiring is facilitated by the use of an angled tip microcatheter (SuperCross), which can be considered as an alternative in patients with difficult side branch wiring in angulated lesions.