Cutting and Stenting in a Heavily Calcified Left <br />
Anterior Descending Artery Lesion

The approach to the highly calcified proximal left anterior descending coronary artery (LAD) lesion remains controversial. Treatment with percutaneous transluminal coronary angioplasty (PTCA) alone has resulted in lower success rates, higher acute complications and increased clinical and angiographic restenosis rates when compared with simple lesions.1,2 Two features may complicate the standard approach of conventional angioplasty and stenting. Intravascular ultrasound (IVUS) data have demonstrated that coronary calcium significantly contributes to decreased vessel compliance.3 This may result in an increased incidence of uncontrolled dissection,4,5 necessitating deployment of stents over a much longer vessel segment, with subsequent increased risk of restenosis. This itself may be further complicated by the loss of sidebranches due to jailing or dissection progressing down the branch as well as the increased risk of restenosis. The second feature is the risk of being unable to “crack” the lesion. This may result in the subsequent inability to adequately deploy or fully expand a stent due to residual stenosis.6,7 An alternative approach is the initial use of rotational atherectomy, aimed at debulking the lesion in order to increase the vessel wall compliance, facilitating stent deployment and expansion.8 We describe a case in which IVUS guidance allowed for adequate dilatation with a cutting balloon and optimization of stent deployment in a patient with a heavily calcified LAD lesion. Case Report. A 57-year-old man presented with a 3-week history of progressive angina with a Canadian Cardiovascular Society functional class of III/IV. Four years prior to his presentation, he suffered an anterior wall myocardial infarction. A dipyridamole-sestamibi nuclear SPECT revealed a partially reversible perfusion defect of the anterior wall. The patient was referred for coronary angiography, which revealed heavily calcified coronary arteries. There was a proximal LAD lesion of 75% diameter stenosis, a lesion of 90% diameter stenosis of the ramus intermedius branch and a non-occlusive plaque in the mid circumflex artery as measured by online quantitative coronary angiography (View System, Electromed, St. Eustache, PQ). Global left ventricular function was preserved with a localized zone of severe anterior hypokinesis as assessed by left ventriculography. Through an 8 French (Fr) Vista Brite tip guiding catheter (Cordis Corporation, Miami, Florida) a 0.014´´ Doppler flow wire (Cardiometrics Inc., Mountain View, California) was positioned in the distal LAD. Pre-intervention IVUS examination (five-64 catheter, Endosonics, Rancho Cordova, California) of the LAD lesion demonstrated a critical long stenosis with severe superficial and deep calcification extending around 360° of the vessel (Figure 1). A Doppler study was then performed, demonstrating significant impairment of coronary flow reserve and a post adenosine study to baseline ratio of 1.4 (Figure 2). In view of these findings, a strategy to increase the radial compliance of this heavily calcified vessel prior to stenting was chosen. A 15-mm long, 3.25 mm cutting balloon (InterVentional Technologies, San Diego, California) crossed the lesion without difficulty and 2 adjacent inflations were performed at the lesion site to nominal 6 atmospheres (atm). Angiography demonstrated an improved lumen with a 30–40% residual stenosis, with no dissection. Repeat IVUS at this stage revealed a minimal luminal diameter (MLD) of 2.1 mm with evidence of scoring or minor dissection of the calcified plaque at the sites of the balloon blades (Figure 3). A 30-mm long Crown stent pre-mounted on a 3.5 mm PowerGrip balloon (Cordis Corporation) was then deployed across the entire lesion at 10 atm with an excellent angiographic result. IVUS at this stage revealed a MLD of 3.1 mm, with the stent well apposed. Due to the pre-intervention dimensions of the vessel, a larger 4.0 mm diameter, 20-mm long Viva balloon (Boston Scientific/Scimed, Inc., Maple Grove, Minnesota) was used to further dilate the stent first distally and then proximally at 10 and 14 atm, respectively, with an excellent angiographic result. A final IVUS examination demonstrated a MLD of 3.5 mm at the site of 360° of tight superficial calcium (Figure 4). Repeat coronary flow reserve measurement revealed that the flow ratio baseline to post adenosine had increased to 4.9 (Figure 5). At 6-month follow-up, the patient remained asymptomatic and dipyridamole-sestamibi nuclear SPECT revealed no reversible perfusion defect. Discussion. The standard approach of conventional angioplasty and stenting of highly calcified proximal LAD lesions remains controversial. This approach may become complicated by decreased vessel compliance due to coronary calcium and by the risk of being unable to “crack” the lesion and the subsequent inability to deploy or fully expand a stent due to residual stenosis. An alternative approach is the initial use of rotational atherectomy, aimed at debulking the lesion in order to increase the vessel wall compliance, facilitating stent deployment and expansion. This may require the use of multiple burrs for upsizing to achieve the desired lumen diameter. This is then followed by conventional angioplasty. Such an option may be time-consuming and costly due to the use of numerous burr sizes. Furthermore, adverse procedural events including spasm, arrhythmia and slow/no reflow are more common with this device.9 It is also contraindicated if an initial balloon inflation results in any but the smallest intimal dissection. Finally, the absolute amount of debulking achieved is limited by the small burr sizes that are available (

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